Initial commitHEADmaster

305 files changed, 6007 insertions, 0 deletions

diff --git a/README.md b/README.md
new file mode 100644
index 0000000..7a7b6b3
--- /dev/null
+++ b/README.md
@@ -0,0 +1,45 @@
+# PyQuest  

+---

+> Repository for the course *Software Construction*, part of the master *Software Engineering* at the *University of Amsterdam*

+---

+

+This repository contains code implementing a Questionnaire Language (QL) in Python.

+

+## Dependencies

+### Python

+Python version 3

+

+#### Packages

+- multimethods

+- PLY

+- PyQt5

+- termcolor

+## Setup

+```

+sudo pip3 install multimethods

+sudo pip3 install ply

+sudo pip3 install pyqt5

+sudo pip3 install termcolor

+```

+

+

+## Running

+```

+python3 pyquest.py

+```

+

+### Optional arguments

+```

+-t, --test	Perform tests.

+```

+

+### GUI Shortcuts

+

+| Shortcut | Action |

+| ------ | ------ |

+| `Ctrl+N`| Create a new .ql file |

+| `Ctrl+O`| Open a .ql file |

+| `Ctrl+S`| Save current .ql file |

+| `Ctrl+Shift+S`| Save as current .ql file |   

+| `Ctrl+R` | Run current .ql file |

+

diff --git a/gui/__pycache__/helper.cpython-35.pyc b/gui/__pycache__/helper.cpython-35.pyc
new file mode 100644
index 0000000..ee2c6ac
--- /dev/null
+++ b/gui/__pycache__/helper.cpython-35.pyc
diff --git a/gui/helper.py b/gui/helper.py
new file mode 100644
index 0000000..615c87a
--- /dev/null
+++ b/gui/helper.py
@@ -0,0 +1,23 @@
+from PyQt5.QtWidgets import QMessageBox
+
+
+def append_file_extension(file_name, extension):
+        if not file_name.endswith('.' + extension):
+            return '{}.{}'.format(file_name, extension)
+        return file_name
+
+
+def error(errors):
+    message = '\n'.join(errors)
+    QMessageBox.critical(QMessageBox(), 'Error', message, QMessageBox.Close, QMessageBox.Escape)
+
+
+def warning(warnings):
+    message = '\n'.join(warnings)
+    QMessageBox.warning(QMessageBox(), 'Warning', message, QMessageBox.Close, QMessageBox.Escape)
+
+
+def check_errors(errors):
+    if errors:
+        error(errors)
+        raise SyntaxError
diff --git a/gui/model/__pycache__/form.cpython-35.pyc b/gui/model/__pycache__/form.cpython-35.pyc
new file mode 100644
index 0000000..cd48947
--- /dev/null
+++ b/gui/model/__pycache__/form.cpython-35.pyc
diff --git a/gui/model/__pycache__/question.cpython-35.pyc b/gui/model/__pycache__/question.cpython-35.pyc
new file mode 100644
index 0000000..64bb4cf
--- /dev/null
+++ b/gui/model/__pycache__/question.cpython-35.pyc
diff --git a/gui/model/form.py b/gui/model/form.py
new file mode 100644
index 0000000..3f045ce
--- /dev/null
+++ b/gui/model/form.py
@@ -0,0 +1,44 @@
+from json import dumps
+
+
+class FormModel:
+    def __init__(self, identifier):
+        self.__identifier = identifier
+        self.__block = []
+
+    @property
+    def identifier(self):
+        return self.__identifier
+
+    @property
+    def block(self):
+        return self.__block
+
+    def to_json(self):
+        return dumps({question.identifier: question.answer.value.get_json_value() for question in self.block})
+
+    def find_question_of_widget(self, widget):
+        for question in self.block:
+            if question.widget == widget:
+                return question
+
+    def update_questions_on_change(self, changed_widget):
+        changed_question = self.find_question_of_widget(changed_widget)
+
+        if changed_question:
+            new_value = changed_question.widget.get_value(changed_question.answer_type)
+            changed_question.answer = changed_question.answer_type.get_literal_node(new_value)
+
+            for question in self.block:
+                result = question.evaluate_visibility_condition(self)
+
+                if result:
+                    question.widget.show()
+                    question.widget_label.show()
+                else:
+                    question.widget.hide()
+                    question.widget_label.hide()
+
+                if question.computed:
+                    answer_result = str(question.evaluate_answer(self))
+                    question.widget.setText(answer_result)
diff --git a/gui/model/question.py b/gui/model/question.py
new file mode 100644
index 0000000..a45d6e2
--- /dev/null
+++ b/gui/model/question.py
@@ -0,0 +1,83 @@
+from gui.widgets.label import Label
+from ql.ast.visitors.expression_evaluator import ExpressionEvaluator
+
+
+class QuestionModel:
+    def __init__(self, label, identifier, answer_type, answer, computed, visibility_condition):
+        self.__label = label
+        self.__identifier = identifier
+        self.__answer_type = answer_type
+        self.__answer = answer
+        self.__computed = computed
+        self.__visibility_condition = visibility_condition
+        self.__widget = None
+        self.__widget_label = None
+
+    @property
+    def label(self):
+        return self.__label
+
+    @property
+    def identifier(self):
+        return self.__identifier
+
+    @property
+    def answer_type(self):
+        return self.__answer_type
+
+    @property
+    def answer(self):
+        return self.__answer
+
+    @answer.setter
+    def answer(self, value):
+        self.__answer = value
+
+    @property
+    def computed(self):
+        return self.__computed
+
+    @property
+    def visibility_condition(self):
+        return self.__visibility_condition
+
+    @property
+    def widget(self):
+        return self.__widget
+
+    @widget.setter
+    def widget(self, value):
+        self.__widget = value
+
+    @property
+    def widget_label(self):
+        return self.__widget_label
+
+    @widget_label.setter
+    def widget_label(self, value):
+        self.__widget_label = value
+
+    def evaluate_visibility_condition(self, form):
+        visitor = ExpressionEvaluator(form)
+        visitor.visit(self.visibility_condition)
+        return visitor.result
+
+    def evaluate_answer(self, form):
+        visitor = ExpressionEvaluator(form)
+        visitor.visit(self.answer)
+        return visitor.result
+
+    def pyqt5_render(self, layout, form, visible=True):
+        self.widget_label = Label(self.label)
+
+        if self.computed:
+            answer_result = str(self.evaluate_answer(form))
+            self.widget = Label(answer_result)
+        else:
+            self.widget = self.answer_type.pyqt5_default_widget()
+
+        if not visible:
+            self.widget.hide()
+            self.widget_label.hide()
+
+        layout.addRow(self.widget_label, self.widget)
diff --git a/gui/widgets/__pycache__/calendar.cpython-35.pyc b/gui/widgets/__pycache__/calendar.cpython-35.pyc
new file mode 100644
index 0000000..fcd150c
--- /dev/null
+++ b/gui/widgets/__pycache__/calendar.cpython-35.pyc
diff --git a/gui/widgets/__pycache__/checkbox.cpython-35.pyc b/gui/widgets/__pycache__/checkbox.cpython-35.pyc
new file mode 100644
index 0000000..49f87fc
--- /dev/null
+++ b/gui/widgets/__pycache__/checkbox.cpython-35.pyc
diff --git a/gui/widgets/__pycache__/double_spinbox.cpython-35.pyc b/gui/widgets/__pycache__/double_spinbox.cpython-35.pyc
new file mode 100644
index 0000000..31d21df
--- /dev/null
+++ b/gui/widgets/__pycache__/double_spinbox.cpython-35.pyc
diff --git a/gui/widgets/__pycache__/label.cpython-35.pyc b/gui/widgets/__pycache__/label.cpython-35.pyc
new file mode 100644
index 0000000..13726bf
--- /dev/null
+++ b/gui/widgets/__pycache__/label.cpython-35.pyc
diff --git a/gui/widgets/__pycache__/line_edit.cpython-35.pyc b/gui/widgets/__pycache__/line_edit.cpython-35.pyc
new file mode 100644
index 0000000..8b314d1
--- /dev/null
+++ b/gui/widgets/__pycache__/line_edit.cpython-35.pyc
diff --git a/gui/widgets/__pycache__/money_spinbox.cpython-35.pyc b/gui/widgets/__pycache__/money_spinbox.cpython-35.pyc
new file mode 100644
index 0000000..f55f3da
--- /dev/null
+++ b/gui/widgets/__pycache__/money_spinbox.cpython-35.pyc
diff --git a/gui/widgets/__pycache__/spinbox.cpython-35.pyc b/gui/widgets/__pycache__/spinbox.cpython-35.pyc
new file mode 100644
index 0000000..d23e28b
--- /dev/null
+++ b/gui/widgets/__pycache__/spinbox.cpython-35.pyc
diff --git a/gui/widgets/calendar.py b/gui/widgets/calendar.py
new file mode 100644
index 0000000..5f09834
--- /dev/null
+++ b/gui/widgets/calendar.py
@@ -0,0 +1,13 @@
+from PyQt5.QtWidgets import QCalendarWidget
+
+
+class CalendarWidget(QCalendarWidget):
+    def __init__(self):
+        super(QCalendarWidget, self).__init__()
+
+    def get_value(self, ql_type):
+        date = self.selectedDate()
+        return ql_type(date.day(), date.month(), date.year())
+
+    def on_change(self, change_event_function):
+        self.selectionChanged.connect(lambda: change_event_function(self))
diff --git a/gui/widgets/checkbox.py b/gui/widgets/checkbox.py
new file mode 100644
index 0000000..d8e32f1
--- /dev/null
+++ b/gui/widgets/checkbox.py
@@ -0,0 +1,12 @@
+from PyQt5.QtWidgets import QCheckBox
+
+
+class CheckBox(QCheckBox):
+    def __init__(self):
+        super(QCheckBox, self).__init__()
+
+    def get_value(self, ql_type):
+        return ql_type(self.isChecked())
+
+    def on_change(self, change_event_function):
+        self.stateChanged.connect(lambda: change_event_function(self))
diff --git a/gui/widgets/double_spinbox.py b/gui/widgets/double_spinbox.py
new file mode 100644
index 0000000..bde201d
--- /dev/null
+++ b/gui/widgets/double_spinbox.py
@@ -0,0 +1,15 @@
+from PyQt5.QtWidgets import QDoubleSpinBox
+
+
+class DoubleSpinBox(QDoubleSpinBox):
+    def __init__(self):
+        super(QDoubleSpinBox, self).__init__()
+        self.setMaximum(2**31 - 1)
+        self.setMinimum(-self.maximum())
+        self.setDecimals(16)
+        
+    def get_value(self, ql_type):
+        return ql_type(self.value())
+
+    def on_change(self, change_event_function):
+        self.valueChanged.connect(lambda: change_event_function(self))
diff --git a/gui/widgets/label.py b/gui/widgets/label.py
new file mode 100644
index 0000000..a0ce233
--- /dev/null
+++ b/gui/widgets/label.py
@@ -0,0 +1,9 @@
+from PyQt5.QtWidgets import QLabel
+
+
+class Label(QLabel):
+    def __init__(self, label):
+        super(QLabel, self).__init__(label)
+
+    def on_change(self, change_event_function):
+        pass
diff --git a/gui/widgets/line_edit.py b/gui/widgets/line_edit.py
new file mode 100644
index 0000000..a87a7b6
--- /dev/null
+++ b/gui/widgets/line_edit.py
@@ -0,0 +1,12 @@
+from PyQt5.QtWidgets import QLineEdit
+
+
+class LineEdit(QLineEdit):
+    def __init__(self):
+        super(QLineEdit, self).__init__()
+
+    def get_value(self, ql_type):
+        return ql_type(self.text())
+
+    def on_change(self, change_event_function):
+        self.textChanged.connect(lambda: change_event_function(self))
diff --git a/gui/widgets/money_spinbox.py b/gui/widgets/money_spinbox.py
new file mode 100644
index 0000000..680a432
--- /dev/null
+++ b/gui/widgets/money_spinbox.py
@@ -0,0 +1,15 @@
+from PyQt5.QtWidgets import QDoubleSpinBox
+
+
+class MoneySpinbox(QDoubleSpinBox):
+    def __init__(self):
+        super(QDoubleSpinBox, self).__init__()
+        self.setPrefix('$')
+        self.setMaximum(2**31 - 1)
+        self.setMinimum(-self.maximum())
+
+    def get_value(self, ql_type):
+        return ql_type(self.value(), self.prefix())
+
+    def on_change(self, change_event_function):
+        self.valueChanged.connect(lambda: change_event_function(self))
diff --git a/gui/widgets/spinbox.py b/gui/widgets/spinbox.py
new file mode 100644
index 0000000..1abb63a
--- /dev/null
+++ b/gui/widgets/spinbox.py
@@ -0,0 +1,14 @@
+from PyQt5.QtWidgets import QSpinBox
+
+
+class SpinBox(QSpinBox):
+    def __init__(self):
+        super(QSpinBox, self).__init__()
+        self.setMaximum(2**31 - 1)
+        self.setMinimum(-self.maximum())
+
+    def get_value(self, ql_type):
+        return ql_type(self.value())
+
+    def on_change(self, change_event_function):
+        self.valueChanged.connect(lambda: change_event_function(self))
diff --git a/gui/windows/__pycache__/form.cpython-35.pyc b/gui/windows/__pycache__/form.cpython-35.pyc
new file mode 100644
index 0000000..d04e617
--- /dev/null
+++ b/gui/windows/__pycache__/form.cpython-35.pyc
diff --git a/gui/windows/__pycache__/main.cpython-35.pyc b/gui/windows/__pycache__/main.cpython-35.pyc
new file mode 100644
index 0000000..3e7dec3
--- /dev/null
+++ b/gui/windows/__pycache__/main.cpython-35.pyc
diff --git a/gui/windows/form.py b/gui/windows/form.py
new file mode 100644
index 0000000..64c05f8
--- /dev/null
+++ b/gui/windows/form.py
@@ -0,0 +1,68 @@
+from PyQt5.QtCore import pyqtSlot
+from PyQt5.QtWidgets import QDialog
+from PyQt5.QtWidgets import QDialogButtonBox
+from PyQt5.QtWidgets import QFileDialog
+from PyQt5.QtWidgets import QFormLayout
+from PyQt5.QtWidgets import QGroupBox
+from PyQt5.QtWidgets import QMessageBox
+from PyQt5.QtWidgets import QVBoxLayout
+
+from gui.helper import append_file_extension
+
+
+class FormWindow(QDialog):
+    def __init__(self, form_model):
+        super(FormWindow, self).__init__()
+        self.__form_model = form_model
+        self.__form_group_box = QGroupBox()
+
+        self.setWindowTitle('Form')
+        self.create_form()
+
+        button_box = QDialogButtonBox(QDialogButtonBox.Save | QDialogButtonBox.Cancel)
+        button_box.accepted.connect(self.accept)
+        button_box.rejected.connect(self.reject)
+
+        main_layout = QVBoxLayout()
+        main_layout.addWidget(self.form_group_box)
+        main_layout.addWidget(button_box)
+        self.setLayout(main_layout)
+
+    @property
+    def form_model(self):
+        return self.__form_model
+
+    @property
+    def form_group_box(self):
+        return self.__form_group_box
+
+    def create_form(self):
+        layout = QFormLayout()
+
+        for question in self.form_model.block:
+            show = question.evaluate_visibility_condition(self.form_model)
+            question.pyqt5_render(layout, self.form_model, show)
+            question.widget.on_change(self.form_model.update_questions_on_change)
+
+        self.form_group_box.setLayout(layout)
+
+    @pyqtSlot(name='accept')
+    def accept(self):
+        file_name, _ = QFileDialog.getSaveFileName(QFileDialog(), 'Save results', self.form_model.identifier,
+                                                   'JSON (*.json);;All Files (*)')
+
+        if file_name:
+            file_name = append_file_extension(file_name, 'json')
+            file = open(file_name, 'w')
+            file.write(self.form_model.to_json())
+            file.close()
+            self.close()
+            QMessageBox.information(QMessageBox(), 'Submission', 'Your answers have been submitted successfully.',
+                                    QMessageBox.Close, QMessageBox.Escape)
+        else:
+            QMessageBox.warning(QMessageBox(), 'Warning', 'Questionnaire results were not saved.',
+                                QMessageBox.Close, QMessageBox.Escape)
+
+    @pyqtSlot(name='reject')
+    def reject(self):
+        self.hide()
diff --git a/gui/windows/main.py b/gui/windows/main.py
new file mode 100644
index 0000000..4dc4ef2
--- /dev/null
+++ b/gui/windows/main.py
@@ -0,0 +1,139 @@
+from PyQt5.QtGui import QIcon

+from PyQt5.QtWidgets import QAction

+from PyQt5.QtWidgets import QFileDialog

+from PyQt5.QtWidgets import QMainWindow

+from PyQt5.QtWidgets import QTextEdit

+

+from gui.helper import append_file_extension

+from gui.helper import check_errors

+from gui.helper import warning

+from gui.windows.form import FormWindow

+from ql.ast.checkers.dependency_checker import DependencyChecker

+from ql.ast.checkers.question_checker import QuestionChecker

+from ql.ast.checkers.reference_checker import ReferenceChecker

+from ql.ast.extractors.extractor import extract_gui_model

+from ql.ast.extractors.extractor import extract_identifier_dependencies

+from ql.ast.extractors.extractor import extract_identifier_scopes

+from ql.ast.extractors.extractor import extract_identifier_types

+from ql.ast.extractors.extractor import extract_questions

+from ql.ast.visitors.type_visitor import TypeVisitor

+from ql.parser.lexer import QLLexer

+from ql.parser.parser import QLParser

+

+

+class MainWindow(QMainWindow):

+    def __init__(self):

+        super().__init__()

+

+        self.setWindowTitle('PyQuest')

+        self.current_file = None

+        self.create_menu_bar()

+        self.text_edit = QTextEdit()

+        self.setCentralWidget(self.text_edit)

+

+        self.show()

+

+    def create_menu_bar(self):

+        menu_bar = self.menuBar()

+

+        new_file = QAction(QIcon(), 'New', self)

+        new_file.setShortcut('Ctrl+N')

+        new_file.setStatusTip('New file')

+        new_file.triggered.connect(self.new_file)

+

+        open_file = QAction(QIcon(), 'Open', self)

+        open_file.setShortcut('Ctrl+O')

+        open_file.setStatusTip('Open file')

+        open_file.triggered.connect(self.open_file)

+

+        save = QAction(QIcon(), 'Save', self)

+        save.setShortcut('Ctrl+S')

+        save.setStatusTip('Save file')

+        save.triggered.connect(self.save)

+

+        save_file = QAction(QIcon(), 'Save as', self)

+        save_file.setShortcut('Ctrl+Shift+S')

+        save_file.setStatusTip('Save file as')

+        save_file.triggered.connect(self.save_file)

+

+        create_form = QAction(QIcon(), 'Create form', self)

+        create_form.setShortcut('Ctrl+R')

+        create_form.setStatusTip('Create form')

+        create_form.triggered.connect(self.create_form)

+

+        file_menu = menu_bar.addMenu('&File')

+        file_menu.addAction(new_file)

+        file_menu.addAction(open_file)

+        file_menu.addAction(save)

+        file_menu.addAction(save_file)

+

+        create_menu = menu_bar.addMenu('&Create')

+        create_menu.addAction(create_form)

+

+    def new_file(self):

+        self.current_file = None

+        self.text_edit.setText('')

+

+    def open_file(self):

+        self.current_file, _ = QFileDialog.getOpenFileName(caption='Open file', directory='/home',

+                                                           filter="Questionnaire language files (*.ql)")

+

+        if self.current_file:

+            with open(self.current_file, 'r') as file:

+                self.text_edit.setText(file.read())

+

+    def save(self):

+        if self.current_file:

+            with open(self.current_file, 'w') as file:

+                file.write(self.text_edit.toPlainText())

+        else:

+            self.save_file()

+

+    def save_file(self):

+        file_name, _ = QFileDialog.getSaveFileName(caption='Save file as', directory='/home',

+                                                   filter='Questionnaire language files (*.ql)')

+

+        if file_name:

+            self.current_file = append_file_extension(file_name, 'ql')

+            with open(self.current_file, 'w') as file:

+                file.write(self.text_edit.toPlainText())

+

+    def create_form(self):

+        textbox_value = self.text_edit.toPlainText()

+        ql_lexer = QLLexer()

+        ql_lexer.build()

+        ql_parser = QLParser()

+        ql_parser.build()

+        empty_form = []

+

+        if not textbox_value:

+            empty_form.append('Empty Form')

+

+        try:

+            check_errors(empty_form)

+            ast = ql_parser.parse(textbox_value, ql_lexer.lexer)

+            parse_errors = ql_parser.errors

+

+            check_errors(parse_errors)

+            reference_errors = ReferenceChecker(extract_identifier_scopes(ast)).errors

+

+            check_errors(reference_errors)

+            dependency_errors = DependencyChecker(extract_identifier_dependencies(ast)).errors

+

+            check_errors(dependency_errors)

+            question_errors = QuestionChecker(extract_questions(ast)).errors

+            question_warnings = QuestionChecker(extract_questions(ast)).warnings

+

+            if question_warnings:

+                warning(question_warnings)

+

+            check_errors(question_errors)

+            type_visitor = TypeVisitor(extract_identifier_types(ast))

+            type_visitor.visit(ast)

+            type_errors = type_visitor.errors

+

+            check_errors(type_errors),

+            dialog = FormWindow(extract_gui_model(ast))

+            dialog.exec_()

+        except SyntaxError:

+            print('Consult application popup error window for information on what went wrong.')

diff --git a/pyquest.py b/pyquest.py
new file mode 100644
index 0000000..caf0726
--- /dev/null
+++ b/pyquest.py
@@ -0,0 +1,43 @@
+from argparse import ArgumentParser
+from sys import argv
+from sys import exit
+
+from PyQt5.QtWidgets import QApplication
+
+from gui.windows.main import MainWindow
+from ql.parser.lexer import QLLexer
+from ql.parser.parser import QLParser
+from ql.test.expression_evaluation.test_expression_evaluation import TestExpressionEvaluation
+from ql.test.lexing.test_lexing import TestLexing
+from ql.test.parsing.test_parsing import TestParsing
+from ql.test.semantic_analysis.test_semantic_analysis import TestSemanticAnalysis
+
+
+def main():
+    parser = ArgumentParser(prog='PyQuest')
+    parser.add_argument('-t', '--test', action='store_true', help="Perform tests.")
+    arguments = parser.parse_args()
+
+    if arguments.test:
+        ql_lexer = QLLexer()
+        ql_lexer.build()
+        ql_parser = QLParser()
+        ql_parser.build()
+
+        test_lexer = TestLexing('ql/test/lexing/', ql_lexer)
+        test_parser = TestParsing('ql/test/parsing/', ql_lexer, ql_parser)
+        test_semantic_analyzer = TestSemanticAnalysis('ql/test/semantic_analysis/', ql_lexer, ql_parser)
+        test_evaluation = TestExpressionEvaluation('ql/test/expression_evaluation/', ql_lexer, ql_parser)
+
+        test_lexer.test()
+        test_parser.test()
+        test_semantic_analyzer.test()
+        test_evaluation.test()
+    else:
+        application = QApplication(argv)
+        main_window = MainWindow()
+        exit(application.exec_())
+
+
+if __name__ == '__main__':
+    main()
diff --git a/ql/ast/checkers/__pycache__/dependency_checker.cpython-35.pyc b/ql/ast/checkers/__pycache__/dependency_checker.cpython-35.pyc
new file mode 100644
index 0000000..5be2eb2
--- /dev/null
+++ b/ql/ast/checkers/__pycache__/dependency_checker.cpython-35.pyc
diff --git a/ql/ast/checkers/__pycache__/question_checker.cpython-35.pyc b/ql/ast/checkers/__pycache__/question_checker.cpython-35.pyc
new file mode 100644
index 0000000..bb81f4a
--- /dev/null
+++ b/ql/ast/checkers/__pycache__/question_checker.cpython-35.pyc
diff --git a/ql/ast/checkers/__pycache__/reference_checker.cpython-35.pyc b/ql/ast/checkers/__pycache__/reference_checker.cpython-35.pyc
new file mode 100644
index 0000000..3bdfae5
--- /dev/null
+++ b/ql/ast/checkers/__pycache__/reference_checker.cpython-35.pyc
diff --git a/ql/ast/checkers/dependency_checker.py b/ql/ast/checkers/dependency_checker.py
new file mode 100644
index 0000000..473ef6b
--- /dev/null
+++ b/ql/ast/checkers/dependency_checker.py
@@ -0,0 +1,44 @@
+class DependencyChecker:
+    def __init__(self, combinations):
+        self.__errors = []
+        self.__check_dependencies(combinations)
+
+    @property
+    def errors(self):
+        return self.__errors
+
+    def __check_dependencies(self, combinations):
+        for (identifier, identifier_children, identifier_metadata) in combinations:
+            children = self.__find_children(identifier, combinations)
+
+            if identifier in children:
+                self.__errors.append('Cyclic dependency detected in question identifiers on line(s) {}'
+                                     .format(str(self.__find_lines(children, combinations))[1:-1]))
+
+    def __find_children(self, identifier, combinations):
+        reference, reference_children, _ = combinations[0]
+
+        if len(combinations) == 1 and identifier == reference:
+            return reference_children
+        elif len(combinations) == 1:
+            return []
+        elif identifier == reference:
+            all_children = []
+
+            for new_identifier in reference_children:
+                all_children += self.__find_children(new_identifier, combinations[1:])
+
+            return all_children + reference_children
+
+        return self.__find_children(identifier, combinations[1:])
+
+    @staticmethod
+    def __find_lines(children, combinations):
+        lines = []
+
+        for identifier, _, metadata in combinations:
+            for child in children:
+                if identifier == child:
+                    lines.append(metadata.line)
+
+        return lines
diff --git a/ql/ast/checkers/question_checker.py b/ql/ast/checkers/question_checker.py
new file mode 100644
index 0000000..5b255d8
--- /dev/null
+++ b/ql/ast/checkers/question_checker.py
@@ -0,0 +1,33 @@
+class QuestionChecker:
+    def __init__(self, questions):
+        self.__errors = []
+        self.__warnings = []
+        self.__check_questions(questions)
+
+    @property
+    def errors(self):
+        return self.__errors
+
+    @property
+    def warnings(self):
+        return self.__warnings
+
+    def __check_questions(self, questions):
+        for question1 in questions:
+            for question2 in questions:
+                if question1 != question2:
+                    equal_labels = question1['label'] == question2['label']
+                    equal_identifiers = question1['identifier'] == question2['identifier']
+                    different_types = question1['answer_type'] != question2['answer_type']
+
+                    if all([equal_labels, equal_identifiers, different_types]):
+                        self.__errors.append('Duplicate questions with different types found on lines {} and {}'
+                                             .format(question1['metadata'].line, question2['metadata'].line))
+
+                    if equal_identifiers:
+                        self.__errors.append('Duplicate question identifiers found on lines {} and {}'
+                                             .format(question1['metadata'].line, question2['metadata'].line))
+
+                    if equal_labels:
+                        self.__warnings.append('Duplicate question labels found on lines {} and {}'
+                                               .format(question1['metadata'].line, question2['metadata'].line))
diff --git a/ql/ast/checkers/reference_checker.py b/ql/ast/checkers/reference_checker.py
new file mode 100644
index 0000000..71407c3
--- /dev/null
+++ b/ql/ast/checkers/reference_checker.py
@@ -0,0 +1,30 @@
+class ReferenceChecker:
+    def __init__(self, table):
+        self.__errors = []
+        self.__check_references(table, [], [])
+
+    @property
+    def errors(self):
+        return self.__errors
+
+    def __check_references(self, table, known_types, unknown_types):
+        (local_known_types, local_unknown_types) = self.__split_known_unknown_types(table)
+        known_types += local_known_types
+        unknown_types += local_unknown_types
+
+        self.__identifier_seen(known_types, unknown_types)
+
+        if table['children']:
+            for child_scope in table['children']:
+                self.__check_references(child_scope, known_types, unknown_types)
+
+    @staticmethod
+    def __split_known_unknown_types(table):
+        known_types = [row['name'] for row in table['content'] if row['type']]
+        unknown_types = [(row['name'], row['line']) for row in table['content'] if not (row['type'])]
+        return known_types, unknown_types
+
+    def __identifier_seen(self, known_types, unknown_types):
+        for (identifier, line) in unknown_types:
+            if not (identifier in known_types):
+                self.__errors.append('Identifier \"{}\" at line {} is unknown'.format(identifier, line))
diff --git a/ql/ast/extractors/__pycache__/extractor.cpython-35.pyc b/ql/ast/extractors/__pycache__/extractor.cpython-35.pyc
new file mode 100644
index 0000000..ceb2379
--- /dev/null
+++ b/ql/ast/extractors/__pycache__/extractor.cpython-35.pyc
diff --git a/ql/ast/extractors/extractor.py b/ql/ast/extractors/extractor.py
new file mode 100644
index 0000000..f86304e
--- /dev/null
+++ b/ql/ast/extractors/extractor.py
@@ -0,0 +1,35 @@
+from ql.ast.visitors.dependency_visitor import DependencyVisitor
+from ql.ast.visitors.identifier_type_visitor import IdentifierTypeVisitor
+from ql.ast.visitors.model_generator import ModelGenerator
+from ql.ast.visitors.question_visitor import QuestionVisitor
+from ql.ast.visitors.reference_visitor import ReferenceVisitor
+
+
+def extract_identifier_dependencies(ast):
+    dependency_visitor = DependencyVisitor()
+    dependency_visitor.visit(ast)
+    return dependency_visitor.identifier_dependencies
+
+
+def extract_identifier_scopes(ast):
+    reference_visitor = ReferenceVisitor()
+    reference_visitor.visit(ast)
+    return reference_visitor.identifier_scopes
+
+
+def extract_identifier_types(ast):
+    identifier_type_visitor = IdentifierTypeVisitor()
+    identifier_type_visitor.visit(ast)
+    return identifier_type_visitor.symbol_table
+
+
+def extract_questions(ast):
+    question_visitor = QuestionVisitor()
+    question_visitor.visit(ast)
+    return question_visitor.questions
+
+
+def extract_gui_model(ast):
+    model_generator = ModelGenerator()
+    model_generator.visit(ast)
+    return model_generator.form
diff --git a/ql/ast/nodes/__pycache__/base.cpython-35.pyc b/ql/ast/nodes/__pycache__/base.cpython-35.pyc
new file mode 100644
index 0000000..d1f8e50
--- /dev/null
+++ b/ql/ast/nodes/__pycache__/base.cpython-35.pyc
diff --git a/ql/ast/nodes/base.py b/ql/ast/nodes/base.py
new file mode 100644
index 0000000..d9196f9
--- /dev/null
+++ b/ql/ast/nodes/base.py
@@ -0,0 +1,10 @@
+class BaseNode:
+    def __init__(self, metadata):
+        self.__metadata = metadata
+
+    def accept(self, visitor):
+        visitor.visit(self)
+
+    @property
+    def metadata(self):
+        return self.__metadata
diff --git a/ql/ast/nodes/expressions/__pycache__/expression.cpython-35.pyc b/ql/ast/nodes/expressions/__pycache__/expression.cpython-35.pyc
new file mode 100644
index 0000000..84ede5c
--- /dev/null
+++ b/ql/ast/nodes/expressions/__pycache__/expression.cpython-35.pyc
diff --git a/ql/ast/nodes/expressions/__pycache__/variable.cpython-35.pyc b/ql/ast/nodes/expressions/__pycache__/variable.cpython-35.pyc
new file mode 100644
index 0000000..b4ff8dc
--- /dev/null
+++ b/ql/ast/nodes/expressions/__pycache__/variable.cpython-35.pyc
diff --git a/ql/ast/nodes/expressions/binary_operators/__pycache__/addition_operator.cpython-35.pyc b/ql/ast/nodes/expressions/binary_operators/__pycache__/addition_operator.cpython-35.pyc
new file mode 100644
index 0000000..bbc8130
--- /dev/null
+++ b/ql/ast/nodes/expressions/binary_operators/__pycache__/addition_operator.cpython-35.pyc
diff --git a/ql/ast/nodes/expressions/binary_operators/__pycache__/and_operator.cpython-35.pyc b/ql/ast/nodes/expressions/binary_operators/__pycache__/and_operator.cpython-35.pyc
new file mode 100644
index 0000000..f004296
--- /dev/null
+++ b/ql/ast/nodes/expressions/binary_operators/__pycache__/and_operator.cpython-35.pyc
diff --git a/ql/ast/nodes/expressions/binary_operators/__pycache__/binary_operator.cpython-35.pyc b/ql/ast/nodes/expressions/binary_operators/__pycache__/binary_operator.cpython-35.pyc
new file mode 100644
index 0000000..18d3fc0
--- /dev/null
+++ b/ql/ast/nodes/expressions/binary_operators/__pycache__/binary_operator.cpython-35.pyc
diff --git a/ql/ast/nodes/expressions/binary_operators/__pycache__/division_operator.cpython-35.pyc b/ql/ast/nodes/expressions/binary_operators/__pycache__/division_operator.cpython-35.pyc
new file mode 100644
index 0000000..9cd8e0a
--- /dev/null
+++ b/ql/ast/nodes/expressions/binary_operators/__pycache__/division_operator.cpython-35.pyc
diff --git a/ql/ast/nodes/expressions/binary_operators/__pycache__/equals_operator.cpython-35.pyc b/ql/ast/nodes/expressions/binary_operators/__pycache__/equals_operator.cpython-35.pyc
new file mode 100644
index 0000000..5d48766
--- /dev/null
+++ b/ql/ast/nodes/expressions/binary_operators/__pycache__/equals_operator.cpython-35.pyc
diff --git a/ql/ast/nodes/expressions/binary_operators/__pycache__/greater_equals_operator.cpython-35.pyc b/ql/ast/nodes/expressions/binary_operators/__pycache__/greater_equals_operator.cpython-35.pyc
new file mode 100644
index 0000000..888c85c
--- /dev/null
+++ b/ql/ast/nodes/expressions/binary_operators/__pycache__/greater_equals_operator.cpython-35.pyc
diff --git a/ql/ast/nodes/expressions/binary_operators/__pycache__/greater_than_operator.cpython-35.pyc b/ql/ast/nodes/expressions/binary_operators/__pycache__/greater_than_operator.cpython-35.pyc
new file mode 100644
index 0000000..be0e395
--- /dev/null
+++ b/ql/ast/nodes/expressions/binary_operators/__pycache__/greater_than_operator.cpython-35.pyc
diff --git a/ql/ast/nodes/expressions/binary_operators/__pycache__/less_equals_operator.cpython-35.pyc b/ql/ast/nodes/expressions/binary_operators/__pycache__/less_equals_operator.cpython-35.pyc
new file mode 100644
index 0000000..b7e8155
--- /dev/null
+++ b/ql/ast/nodes/expressions/binary_operators/__pycache__/less_equals_operator.cpython-35.pyc
diff --git a/ql/ast/nodes/expressions/binary_operators/__pycache__/less_than_operator.cpython-35.pyc b/ql/ast/nodes/expressions/binary_operators/__pycache__/less_than_operator.cpython-35.pyc
new file mode 100644
index 0000000..850a39c
--- /dev/null
+++ b/ql/ast/nodes/expressions/binary_operators/__pycache__/less_than_operator.cpython-35.pyc
diff --git a/ql/ast/nodes/expressions/binary_operators/__pycache__/multiplication_operator.cpython-35.pyc b/ql/ast/nodes/expressions/binary_operators/__pycache__/multiplication_operator.cpython-35.pyc
new file mode 100644
index 0000000..ff0e1ab
--- /dev/null
+++ b/ql/ast/nodes/expressions/binary_operators/__pycache__/multiplication_operator.cpython-35.pyc
diff --git a/ql/ast/nodes/expressions/binary_operators/__pycache__/not_equals_operator.cpython-35.pyc b/ql/ast/nodes/expressions/binary_operators/__pycache__/not_equals_operator.cpython-35.pyc
new file mode 100644
index 0000000..fe666cf
--- /dev/null
+++ b/ql/ast/nodes/expressions/binary_operators/__pycache__/not_equals_operator.cpython-35.pyc
diff --git a/ql/ast/nodes/expressions/binary_operators/__pycache__/or_operator.cpython-35.pyc b/ql/ast/nodes/expressions/binary_operators/__pycache__/or_operator.cpython-35.pyc
new file mode 100644
index 0000000..0b81fc3
--- /dev/null
+++ b/ql/ast/nodes/expressions/binary_operators/__pycache__/or_operator.cpython-35.pyc
diff --git a/ql/ast/nodes/expressions/binary_operators/__pycache__/subtraction_operator.cpython-35.pyc b/ql/ast/nodes/expressions/binary_operators/__pycache__/subtraction_operator.cpython-35.pyc
new file mode 100644
index 0000000..cd89879
--- /dev/null
+++ b/ql/ast/nodes/expressions/binary_operators/__pycache__/subtraction_operator.cpython-35.pyc
diff --git a/ql/ast/nodes/expressions/binary_operators/addition_operator.py b/ql/ast/nodes/expressions/binary_operators/addition_operator.py
new file mode 100644
index 0000000..d6e4506
--- /dev/null
+++ b/ql/ast/nodes/expressions/binary_operators/addition_operator.py
@@ -0,0 +1,27 @@
+from ql.ast.nodes.expressions.binary_operators.binary_operator import BinaryOperatorNode
+from ql.types.decimal import QLDecimal
+from ql.types.integer import QLInteger
+from ql.types.money import QLMoney
+from ql.types.undefined import QLUndefined
+
+
+class AdditionOperatorNode(BinaryOperatorNode):
+    def __init__(self, metadata, expression_type, left_expression, right_expression, value):
+        super(AdditionOperatorNode, self).__init__(metadata, expression_type,
+                                                   left_expression, right_expression, value)
+        self.__valid_types = {
+            (QLDecimal, QLDecimal): QLDecimal,
+            (QLDecimal, QLInteger): QLDecimal,
+            (QLInteger, QLInteger): QLInteger,
+            (QLInteger, QLDecimal): QLDecimal,
+            (QLMoney, QLMoney):     QLMoney,
+        }
+
+    def get_result_type(self):
+        if self.__valid_types.get((self.left_expression.expression_type, self.right_expression.expression_type)):
+            return self.__valid_types.get((self.left_expression.expression_type, self.right_expression.expression_type))
+
+        return QLUndefined
+
+    def evaluate(self):
+        self.value = self.left_expression.value + self.right_expression.value
diff --git a/ql/ast/nodes/expressions/binary_operators/and_operator.py b/ql/ast/nodes/expressions/binary_operators/and_operator.py
new file mode 100644
index 0000000..5981a6b
--- /dev/null
+++ b/ql/ast/nodes/expressions/binary_operators/and_operator.py
@@ -0,0 +1,21 @@
+from ql.ast.nodes.expressions.binary_operators.binary_operator import BinaryOperatorNode
+from ql.types.boolean import QLBoolean
+from ql.types.undefined import QLUndefined
+
+
+class AndOperatorNode(BinaryOperatorNode):
+    def __init__(self, metadata, expression_type, left_expression, right_expression, value):
+        super(AndOperatorNode, self).__init__(metadata, expression_type,
+                                              left_expression, right_expression, value)
+        self.__valid_types = {
+            (QLBoolean, QLBoolean): QLBoolean,
+        }
+
+    def get_result_type(self):
+        if self.__valid_types.get((self.left_expression.expression_type, self.right_expression.expression_type)):
+            return self.__valid_types.get((self.left_expression.expression_type, self.right_expression.expression_type))
+
+        return QLUndefined
+
+    def evaluate(self):
+        self.value = self.left_expression.value and self.right_expression.value
diff --git a/ql/ast/nodes/expressions/binary_operators/binary_operator.py b/ql/ast/nodes/expressions/binary_operators/binary_operator.py
new file mode 100644
index 0000000..048d927
--- /dev/null
+++ b/ql/ast/nodes/expressions/binary_operators/binary_operator.py
@@ -0,0 +1,17 @@
+from ql.ast.nodes.expressions.expression import ExpressionNode
+
+
+class BinaryOperatorNode(ExpressionNode):
+    def __init__(self, metadata, expression_type, left_expression, right_expression, value):
+        super(BinaryOperatorNode, self).__init__(metadata, expression_type, value)
+        self.__left_expression = left_expression
+        self.__right_expression = right_expression
+
+    @property
+    def left_expression(self):
+        return self.__left_expression
+
+    @property
+    def right_expression(self):
+        return self.__right_expression
+
diff --git a/ql/ast/nodes/expressions/binary_operators/division_operator.py b/ql/ast/nodes/expressions/binary_operators/division_operator.py
new file mode 100644
index 0000000..16d5063
--- /dev/null
+++ b/ql/ast/nodes/expressions/binary_operators/division_operator.py
@@ -0,0 +1,31 @@
+from ql.ast.nodes.expressions.binary_operators.binary_operator import BinaryOperatorNode
+from ql.types.decimal import QLDecimal
+from ql.types.integer import QLInteger
+from ql.types.money import QLMoney
+from ql.types.undefined import QLUndefined
+
+
+class DivisionOperatorNode(BinaryOperatorNode):
+    def __init__(self, metadata, expression_type, left_expression, right_expression, value):
+        super(DivisionOperatorNode, self).__init__(metadata, expression_type,
+                                                   left_expression, right_expression, value)
+        self.__valid_types = {
+            (QLDecimal, QLDecimal): QLDecimal,
+            (QLDecimal, QLInteger): QLDecimal,
+            (QLInteger, QLInteger): QLDecimal,
+            (QLInteger, QLDecimal): QLDecimal,
+            (QLMoney, QLDecimal):   QLMoney,
+            (QLMoney, QLInteger):   QLMoney,
+        }
+
+    def get_result_type(self):
+        if self.__valid_types.get((self.left_expression.expression_type, self.right_expression.expression_type)):
+            return self.__valid_types.get((self.left_expression.expression_type, self.right_expression.expression_type))
+
+        return QLUndefined
+
+    def evaluate(self):
+        try:
+            self.value = self.left_expression.value / self.right_expression.value
+        except ZeroDivisionError:
+            self.value = QLUndefined()
diff --git a/ql/ast/nodes/expressions/binary_operators/equals_operator.py b/ql/ast/nodes/expressions/binary_operators/equals_operator.py
new file mode 100644
index 0000000..21315f9
--- /dev/null
+++ b/ql/ast/nodes/expressions/binary_operators/equals_operator.py
@@ -0,0 +1,15 @@
+from ql.ast.nodes.expressions.binary_operators.binary_operator import BinaryOperatorNode
+from ql.types.boolean import QLBoolean
+
+
+class EqualsOperatorNode(BinaryOperatorNode):
+    def __init__(self, metadata, expression_type, left_expression, right_expression, value):
+        super(EqualsOperatorNode, self).__init__(metadata, expression_type,
+                                                 left_expression, right_expression, value)
+
+    @staticmethod
+    def get_result_type():
+        return QLBoolean
+
+    def evaluate(self):
+        self.value = self.left_expression.value == self.right_expression.value
diff --git a/ql/ast/nodes/expressions/binary_operators/greater_equals_operator.py b/ql/ast/nodes/expressions/binary_operators/greater_equals_operator.py
new file mode 100644
index 0000000..0512688
--- /dev/null
+++ b/ql/ast/nodes/expressions/binary_operators/greater_equals_operator.py
@@ -0,0 +1,30 @@
+from ql.ast.nodes.expressions.binary_operators.binary_operator import BinaryOperatorNode
+from ql.types.boolean import QLBoolean
+from ql.types.date import QLDate
+from ql.types.decimal import QLDecimal
+from ql.types.integer import QLInteger
+from ql.types.money import QLMoney
+from ql.types.undefined import QLUndefined
+
+
+class GreaterEqualsOperatorNode(BinaryOperatorNode):
+    def __init__(self, metadata, expression_type, left_expression, right_expression, value):
+        super(GreaterEqualsOperatorNode, self).__init__(metadata, expression_type,
+                                                        left_expression, right_expression, value)
+        self.__valid_types = [
+            (QLDate,    QLDate),
+            (QLDecimal, QLDecimal),
+            (QLDecimal, QLInteger),
+            (QLInteger, QLInteger),
+            (QLInteger, QLDecimal),
+            (QLMoney,   QLMoney),
+        ]
+
+    def get_result_type(self):
+        if (self.left_expression.expression_type, self.right_expression.expression_type) in self.__valid_types:
+            return QLBoolean
+
+        return QLUndefined
+
+    def evaluate(self):
+        self.value = self.left_expression.value >= self.right_expression.value
diff --git a/ql/ast/nodes/expressions/binary_operators/greater_than_operator.py b/ql/ast/nodes/expressions/binary_operators/greater_than_operator.py
new file mode 100644
index 0000000..460c909
--- /dev/null
+++ b/ql/ast/nodes/expressions/binary_operators/greater_than_operator.py
@@ -0,0 +1,30 @@
+from ql.ast.nodes.expressions.binary_operators.binary_operator import BinaryOperatorNode
+from ql.types.boolean import QLBoolean
+from ql.types.date import QLDate
+from ql.types.decimal import QLDecimal
+from ql.types.integer import QLInteger
+from ql.types.money import QLMoney
+from ql.types.undefined import QLUndefined
+
+
+class GreaterThanOperatorNode(BinaryOperatorNode):
+    def __init__(self, metadata, expression_type, left_expression, right_expression, value):
+        super(GreaterThanOperatorNode, self).__init__(metadata, expression_type,
+                                                      left_expression, right_expression, value)
+        self.__valid_types = [
+            (QLDate,    QLDate),
+            (QLDecimal, QLDecimal),
+            (QLDecimal, QLInteger),
+            (QLInteger, QLInteger),
+            (QLInteger, QLDecimal),
+            (QLMoney,   QLMoney),
+        ]
+
+    def get_result_type(self):
+        if (self.left_expression.expression_type, self.right_expression.expression_type) in self.__valid_types:
+            return QLBoolean
+
+        return QLUndefined
+
+    def evaluate(self):
+        self.value = self.left_expression.value > self.right_expression.value
diff --git a/ql/ast/nodes/expressions/binary_operators/less_equals_operator.py b/ql/ast/nodes/expressions/binary_operators/less_equals_operator.py
new file mode 100644
index 0000000..f5b86df
--- /dev/null
+++ b/ql/ast/nodes/expressions/binary_operators/less_equals_operator.py
@@ -0,0 +1,30 @@
+from ql.ast.nodes.expressions.binary_operators.binary_operator import BinaryOperatorNode
+from ql.types.boolean import QLBoolean
+from ql.types.date import QLDate
+from ql.types.decimal import QLDecimal
+from ql.types.integer import QLInteger
+from ql.types.money import QLMoney
+from ql.types.undefined import QLUndefined
+
+
+class LessEqualsOperatorNode(BinaryOperatorNode):
+    def __init__(self, metadata, expression_type, left_expression, right_expression, value):
+        super(LessEqualsOperatorNode, self).__init__(metadata, expression_type,
+                                                     left_expression, right_expression, value)
+        self.__valid_types = [
+            (QLDate,    QLDate),
+            (QLDecimal, QLDecimal),
+            (QLDecimal, QLInteger),
+            (QLInteger, QLInteger),
+            (QLInteger, QLDecimal),
+            (QLMoney,   QLMoney),
+        ]
+
+    def get_result_type(self):
+        if (self.left_expression.expression_type, self.right_expression.expression_type) in self.__valid_types:
+            return QLBoolean
+
+        return QLUndefined
+
+    def evaluate(self):
+        self.value = self.left_expression.value <= self.right_expression.value
diff --git a/ql/ast/nodes/expressions/binary_operators/less_than_operator.py b/ql/ast/nodes/expressions/binary_operators/less_than_operator.py
new file mode 100644
index 0000000..65b456d
--- /dev/null
+++ b/ql/ast/nodes/expressions/binary_operators/less_than_operator.py
@@ -0,0 +1,30 @@
+from ql.ast.nodes.expressions.binary_operators.binary_operator import BinaryOperatorNode
+from ql.types.boolean import QLBoolean
+from ql.types.date import QLDate
+from ql.types.decimal import QLDecimal
+from ql.types.integer import QLInteger
+from ql.types.money import QLMoney
+from ql.types.undefined import QLUndefined
+
+
+class LessThanOperatorNode(BinaryOperatorNode):
+    def __init__(self, metadata, expression_type, left_expression, right_expression, value):
+        super(LessThanOperatorNode, self).__init__(metadata, expression_type,
+                                                   left_expression, right_expression, value)
+        self.__valid_types = [
+            (QLDate,    QLDate),
+            (QLDecimal, QLDecimal),
+            (QLDecimal, QLInteger),
+            (QLInteger, QLInteger),
+            (QLInteger, QLDecimal),
+            (QLMoney,   QLMoney),
+        ]
+
+    def get_result_type(self):
+        if (self.left_expression.expression_type, self.right_expression.expression_type) in self.__valid_types:
+            return QLBoolean
+
+        return QLUndefined
+
+    def evaluate(self):
+        self.value = self.left_expression.value < self.right_expression.value
diff --git a/ql/ast/nodes/expressions/binary_operators/multiplication_operator.py b/ql/ast/nodes/expressions/binary_operators/multiplication_operator.py
new file mode 100644
index 0000000..b014c0e
--- /dev/null
+++ b/ql/ast/nodes/expressions/binary_operators/multiplication_operator.py
@@ -0,0 +1,30 @@
+from ql.ast.nodes.expressions.binary_operators.binary_operator import BinaryOperatorNode
+from ql.types.decimal import QLDecimal
+from ql.types.integer import QLInteger
+from ql.types.money import QLMoney
+from ql.types.undefined import QLUndefined
+
+
+class MultiplicationOperatorNode(BinaryOperatorNode):
+    def __init__(self, metadata, expression_type, left_expression, right_expression, value):
+        super(MultiplicationOperatorNode, self).__init__(metadata, expression_type,
+                                                         left_expression, right_expression, value)
+        self.__valid_types = {
+            (QLDecimal, QLDecimal): QLDecimal,
+            (QLDecimal, QLInteger): QLDecimal,
+            (QLDecimal, QLMoney):   QLMoney,
+            (QLInteger, QLInteger): QLInteger,
+            (QLInteger, QLDecimal): QLDecimal,
+            (QLInteger, QLMoney):   QLMoney,
+            (QLMoney, QLDecimal):   QLMoney,
+            (QLMoney, QLInteger):   QLMoney,
+        }
+
+    def get_result_type(self):
+        if self.__valid_types.get((self.left_expression.expression_type, self.right_expression.expression_type)):
+            return self.__valid_types.get((self.left_expression.expression_type, self.right_expression.expression_type))
+
+        return QLUndefined
+
+    def evaluate(self):
+        self.value = self.left_expression.value * self.right_expression.value
diff --git a/ql/ast/nodes/expressions/binary_operators/not_equals_operator.py b/ql/ast/nodes/expressions/binary_operators/not_equals_operator.py
new file mode 100644
index 0000000..3be2e5f
--- /dev/null
+++ b/ql/ast/nodes/expressions/binary_operators/not_equals_operator.py
@@ -0,0 +1,15 @@
+from ql.ast.nodes.expressions.binary_operators.binary_operator import BinaryOperatorNode
+from ql.types.boolean import QLBoolean
+
+
+class NotEqualsOperatorNode(BinaryOperatorNode):
+    def __init__(self, metadata, expression_type, left_expression, right_expression, value):
+        super(NotEqualsOperatorNode, self).__init__(metadata, expression_type,
+                                                    left_expression, right_expression, value)
+
+    @staticmethod
+    def get_result_type():
+        return QLBoolean
+
+    def evaluate(self):
+        self.value = self.left_expression.value != self.right_expression.value
diff --git a/ql/ast/nodes/expressions/binary_operators/or_operator.py b/ql/ast/nodes/expressions/binary_operators/or_operator.py
new file mode 100644
index 0000000..4314868
--- /dev/null
+++ b/ql/ast/nodes/expressions/binary_operators/or_operator.py
@@ -0,0 +1,21 @@
+from ql.ast.nodes.expressions.binary_operators.binary_operator import BinaryOperatorNode
+from ql.types.boolean import QLBoolean
+from ql.types.undefined import QLUndefined
+
+
+class OrOperatorNode(BinaryOperatorNode):
+    def __init__(self, metadata, expression_type, left_expression, right_expression, value):
+        super(OrOperatorNode, self).__init__(metadata, expression_type,
+                                             left_expression, right_expression, value)
+        self.__valid_types = {
+            (QLBoolean, QLBoolean): QLBoolean,
+        }
+
+    def get_result_type(self):
+        if self.__valid_types.get((self.left_expression.expression_type, self.right_expression.expression_type)):
+            return self.__valid_types.get((self.left_expression.expression_type, self.right_expression.expression_type))
+
+        return QLUndefined
+
+    def evaluate(self):
+        self.value = self.left_expression.value or self.right_expression.value
diff --git a/ql/ast/nodes/expressions/binary_operators/subtraction_operator.py b/ql/ast/nodes/expressions/binary_operators/subtraction_operator.py
new file mode 100644
index 0000000..8ebda15
--- /dev/null
+++ b/ql/ast/nodes/expressions/binary_operators/subtraction_operator.py
@@ -0,0 +1,27 @@
+from ql.ast.nodes.expressions.binary_operators.binary_operator import BinaryOperatorNode
+from ql.types.decimal import QLDecimal
+from ql.types.integer import QLInteger
+from ql.types.money import QLMoney
+from ql.types.undefined import QLUndefined
+
+
+class SubtractionOperatorNode(BinaryOperatorNode):
+    def __init__(self, metadata, expression_type, left_expression, right_expression, value):
+        super(SubtractionOperatorNode, self).__init__(metadata, expression_type,
+                                                      left_expression, right_expression, value)
+        self.__valid_types = {
+            (QLDecimal, QLDecimal): QLDecimal,
+            (QLDecimal, QLInteger): QLDecimal,
+            (QLInteger, QLInteger): QLInteger,
+            (QLInteger, QLDecimal): QLDecimal,
+            (QLMoney, QLMoney):     QLMoney,
+        }
+
+    def get_result_type(self):
+        if self.__valid_types.get((self.left_expression.expression_type, self.right_expression.expression_type)):
+            return self.__valid_types.get((self.left_expression.expression_type, self.right_expression.expression_type))
+
+        return QLUndefined
+
+    def evaluate(self):
+        self.value = self.left_expression.value - self.right_expression.value
diff --git a/ql/ast/nodes/expressions/expression.py b/ql/ast/nodes/expressions/expression.py
new file mode 100644
index 0000000..1364c0b
--- /dev/null
+++ b/ql/ast/nodes/expressions/expression.py
@@ -0,0 +1,24 @@
+from ql.ast.nodes.base import BaseNode
+
+
+class ExpressionNode(BaseNode):
+    def __init__(self, metadata, expression_type, value):
+        super(ExpressionNode, self).__init__(metadata)
+        self.__expression_type = expression_type
+        self.__value = value
+
+    @property
+    def expression_type(self):
+        return self.__expression_type
+
+    @expression_type.setter
+    def expression_type(self, value):
+        self.__expression_type = value
+
+    @property
+    def value(self):
+        return self.__value
+
+    @value.setter
+    def value(self, value):
+        self.__value = value
diff --git a/ql/ast/nodes/expressions/literals/__pycache__/boolean_literal.cpython-35.pyc b/ql/ast/nodes/expressions/literals/__pycache__/boolean_literal.cpython-35.pyc
new file mode 100644
index 0000000..a6d43b1
--- /dev/null
+++ b/ql/ast/nodes/expressions/literals/__pycache__/boolean_literal.cpython-35.pyc
diff --git a/ql/ast/nodes/expressions/literals/__pycache__/date_literal.cpython-35.pyc b/ql/ast/nodes/expressions/literals/__pycache__/date_literal.cpython-35.pyc
new file mode 100644
index 0000000..33abf57
--- /dev/null
+++ b/ql/ast/nodes/expressions/literals/__pycache__/date_literal.cpython-35.pyc
diff --git a/ql/ast/nodes/expressions/literals/__pycache__/decimal_literal.cpython-35.pyc b/ql/ast/nodes/expressions/literals/__pycache__/decimal_literal.cpython-35.pyc
new file mode 100644
index 0000000..145ab16
--- /dev/null
+++ b/ql/ast/nodes/expressions/literals/__pycache__/decimal_literal.cpython-35.pyc
diff --git a/ql/ast/nodes/expressions/literals/__pycache__/integer_literal.cpython-35.pyc b/ql/ast/nodes/expressions/literals/__pycache__/integer_literal.cpython-35.pyc
new file mode 100644
index 0000000..33f5c62
--- /dev/null
+++ b/ql/ast/nodes/expressions/literals/__pycache__/integer_literal.cpython-35.pyc
diff --git a/ql/ast/nodes/expressions/literals/__pycache__/literal.cpython-35.pyc b/ql/ast/nodes/expressions/literals/__pycache__/literal.cpython-35.pyc
new file mode 100644
index 0000000..98af8e6
--- /dev/null
+++ b/ql/ast/nodes/expressions/literals/__pycache__/literal.cpython-35.pyc
diff --git a/ql/ast/nodes/expressions/literals/__pycache__/money_literal.cpython-35.pyc b/ql/ast/nodes/expressions/literals/__pycache__/money_literal.cpython-35.pyc
new file mode 100644
index 0000000..9dbf5d0
--- /dev/null
+++ b/ql/ast/nodes/expressions/literals/__pycache__/money_literal.cpython-35.pyc
diff --git a/ql/ast/nodes/expressions/literals/__pycache__/string_literal.cpython-35.pyc b/ql/ast/nodes/expressions/literals/__pycache__/string_literal.cpython-35.pyc
new file mode 100644
index 0000000..dbb3f72
--- /dev/null
+++ b/ql/ast/nodes/expressions/literals/__pycache__/string_literal.cpython-35.pyc
diff --git a/ql/ast/nodes/expressions/literals/__pycache__/undefined_literal.cpython-35.pyc b/ql/ast/nodes/expressions/literals/__pycache__/undefined_literal.cpython-35.pyc
new file mode 100644
index 0000000..73ce02b
--- /dev/null
+++ b/ql/ast/nodes/expressions/literals/__pycache__/undefined_literal.cpython-35.pyc
diff --git a/ql/ast/nodes/expressions/literals/boolean_literal.py b/ql/ast/nodes/expressions/literals/boolean_literal.py
new file mode 100644
index 0000000..234e548
--- /dev/null
+++ b/ql/ast/nodes/expressions/literals/boolean_literal.py
@@ -0,0 +1,6 @@
+from ql.ast.nodes.expressions.literals.literal import LiteralNode
+
+
+class BooleanNode(LiteralNode):
+    def __init__(self, metadata, expression_type, value):
+        super(BooleanNode, self).__init__(metadata, expression_type, value)
diff --git a/ql/ast/nodes/expressions/literals/date_literal.py b/ql/ast/nodes/expressions/literals/date_literal.py
new file mode 100644
index 0000000..971ab58
--- /dev/null
+++ b/ql/ast/nodes/expressions/literals/date_literal.py
@@ -0,0 +1,6 @@
+from ql.ast.nodes.expressions.literals.literal import LiteralNode
+
+
+class DateNode(LiteralNode):
+    def __init__(self, metadata, expression_type, value):
+        super(DateNode, self).__init__(metadata, expression_type, value)
diff --git a/ql/ast/nodes/expressions/literals/decimal_literal.py b/ql/ast/nodes/expressions/literals/decimal_literal.py
new file mode 100644
index 0000000..7cc4eb5
--- /dev/null
+++ b/ql/ast/nodes/expressions/literals/decimal_literal.py
@@ -0,0 +1,6 @@
+from ql.ast.nodes.expressions.literals.literal import LiteralNode
+
+
+class DecimalNode(LiteralNode):
+    def __init__(self, metadata, expression_type, value):
+        super(DecimalNode, self).__init__(metadata, expression_type, value)
diff --git a/ql/ast/nodes/expressions/literals/integer_literal.py b/ql/ast/nodes/expressions/literals/integer_literal.py
new file mode 100644
index 0000000..36923f9
--- /dev/null
+++ b/ql/ast/nodes/expressions/literals/integer_literal.py
@@ -0,0 +1,6 @@
+from ql.ast.nodes.expressions.literals.literal import LiteralNode
+
+
+class IntegerNode(LiteralNode):
+    def __init__(self, metadata, expression_type, value):
+        super(IntegerNode, self).__init__(metadata, expression_type, value)
diff --git a/ql/ast/nodes/expressions/literals/literal.py b/ql/ast/nodes/expressions/literals/literal.py
new file mode 100644
index 0000000..a0e03ae
--- /dev/null
+++ b/ql/ast/nodes/expressions/literals/literal.py
@@ -0,0 +1,14 @@
+from ql.ast.nodes.expressions.expression import ExpressionNode
+
+
+class LiteralNode(ExpressionNode):
+    def __init__(self, metadata, expression_type, value):
+        super(LiteralNode, self).__init__(metadata, expression_type, value)
+
+    @ExpressionNode.expression_type.setter
+    def expression_type(self, unused):
+        pass
+
+    @ExpressionNode.value.setter
+    def value(self, unused):
+        pass
diff --git a/ql/ast/nodes/expressions/literals/money_literal.py b/ql/ast/nodes/expressions/literals/money_literal.py
new file mode 100644
index 0000000..119e5ff
--- /dev/null
+++ b/ql/ast/nodes/expressions/literals/money_literal.py
@@ -0,0 +1,6 @@
+from ql.ast.nodes.expressions.literals.literal import LiteralNode
+
+
+class MoneyNode(LiteralNode):
+    def __init__(self, metadata, expression_type, value):
+        super(MoneyNode, self).__init__(metadata, expression_type, value)
diff --git a/ql/ast/nodes/expressions/literals/string_literal.py b/ql/ast/nodes/expressions/literals/string_literal.py
new file mode 100644
index 0000000..4fac895
--- /dev/null
+++ b/ql/ast/nodes/expressions/literals/string_literal.py
@@ -0,0 +1,6 @@
+from ql.ast.nodes.expressions.literals.literal import LiteralNode
+
+
+class StringNode(LiteralNode):
+    def __init__(self, metadata, expression_type, value):
+        super(StringNode, self).__init__(metadata, expression_type, value)
diff --git a/ql/ast/nodes/expressions/literals/undefined_literal.py b/ql/ast/nodes/expressions/literals/undefined_literal.py
new file mode 100644
index 0000000..4109df6
--- /dev/null
+++ b/ql/ast/nodes/expressions/literals/undefined_literal.py
@@ -0,0 +1,6 @@
+from ql.ast.nodes.expressions.literals.literal import LiteralNode
+
+
+class UndefinedNode(LiteralNode):
+    def __init__(self, metadata, expression_type, value):
+        super(UndefinedNode, self).__init__(metadata, expression_type, value)
diff --git a/ql/ast/nodes/expressions/unary_operators/__pycache__/negation_operator.cpython-35.pyc b/ql/ast/nodes/expressions/unary_operators/__pycache__/negation_operator.cpython-35.pyc
new file mode 100644
index 0000000..9a6e409
--- /dev/null
+++ b/ql/ast/nodes/expressions/unary_operators/__pycache__/negation_operator.cpython-35.pyc
diff --git a/ql/ast/nodes/expressions/unary_operators/__pycache__/negative_operator.cpython-35.pyc b/ql/ast/nodes/expressions/unary_operators/__pycache__/negative_operator.cpython-35.pyc
new file mode 100644
index 0000000..45ad495
--- /dev/null
+++ b/ql/ast/nodes/expressions/unary_operators/__pycache__/negative_operator.cpython-35.pyc
diff --git a/ql/ast/nodes/expressions/unary_operators/__pycache__/unary_operator.cpython-35.pyc b/ql/ast/nodes/expressions/unary_operators/__pycache__/unary_operator.cpython-35.pyc
new file mode 100644
index 0000000..f72b4f0
--- /dev/null
+++ b/ql/ast/nodes/expressions/unary_operators/__pycache__/unary_operator.cpython-35.pyc
diff --git a/ql/ast/nodes/expressions/unary_operators/negation_operator.py b/ql/ast/nodes/expressions/unary_operators/negation_operator.py
new file mode 100644
index 0000000..7b6b0c5
--- /dev/null
+++ b/ql/ast/nodes/expressions/unary_operators/negation_operator.py
@@ -0,0 +1,20 @@
+from ql.ast.nodes.expressions.unary_operators.unary_operator import UnaryOperatorNode
+from ql.types.boolean import QLBoolean
+from ql.types.undefined import QLUndefined
+
+
+class NegationOperatorNode(UnaryOperatorNode):
+    def __init__(self, metadata, expression_type, expression, value):
+        super(NegationOperatorNode, self).__init__(metadata, expression_type, expression, value)
+        self.__valid_types = {
+            QLBoolean: QLBoolean,
+        }
+
+    def get_result_type(self):
+        if self.__valid_types.get(self.expression.expression_type):
+            return self.__valid_types.get(self.expression.expression_type)
+
+        return QLUndefined
+
+    def evaluate(self):
+        self.value = QLBoolean(not self.expression.value)
diff --git a/ql/ast/nodes/expressions/unary_operators/negative_operator.py b/ql/ast/nodes/expressions/unary_operators/negative_operator.py
new file mode 100644
index 0000000..359ed2e
--- /dev/null
+++ b/ql/ast/nodes/expressions/unary_operators/negative_operator.py
@@ -0,0 +1,23 @@
+from ql.ast.nodes.expressions.unary_operators.unary_operator import UnaryOperatorNode
+from ql.types.decimal import QLDecimal
+from ql.types.integer import QLInteger
+from ql.types.money import QLMoney
+from ql.types.undefined import QLUndefined
+
+
+class NegativeOperatorNode(UnaryOperatorNode):
+    def __init__(self, metadata, expression_type, expression, value):
+        super(NegativeOperatorNode, self).__init__(metadata, expression_type, expression, value)
+        self.__valid_types = {
+            QLDecimal: QLDecimal,
+            QLInteger: QLInteger,
+            QLMoney: QLMoney}
+
+    def get_result_type(self):
+        if self.__valid_types.get(self.expression.expression_type):
+            return self.__valid_types.get(self.expression.expression_type)
+
+        return QLUndefined
+
+    def evaluate(self):
+        self.value = -self.expression.value
diff --git a/ql/ast/nodes/expressions/unary_operators/unary_operator.py b/ql/ast/nodes/expressions/unary_operators/unary_operator.py
new file mode 100644
index 0000000..fa75249
--- /dev/null
+++ b/ql/ast/nodes/expressions/unary_operators/unary_operator.py
@@ -0,0 +1,11 @@
+from ql.ast.nodes.expressions.expression import ExpressionNode
+
+
+class UnaryOperatorNode(ExpressionNode):
+    def __init__(self, metadata, expression_type, expression, value):
+        super(UnaryOperatorNode, self).__init__(metadata, expression_type, value)
+        self.__expression = expression
+
+    @property
+    def expression(self):
+        return self.__expression
diff --git a/ql/ast/nodes/expressions/variable.py b/ql/ast/nodes/expressions/variable.py
new file mode 100644
index 0000000..c126372
--- /dev/null
+++ b/ql/ast/nodes/expressions/variable.py
@@ -0,0 +1,11 @@
+from ql.ast.nodes.expressions.expression import ExpressionNode
+
+
+class VariableNode(ExpressionNode):
+    def __init__(self, metadata, expression_type, identifier, value):
+        super(VariableNode, self).__init__(metadata, expression_type, value)
+        self.__identifier = identifier
+
+    @property
+    def identifier(self):
+        return self.__identifier
diff --git a/ql/ast/nodes/statements/__pycache__/block_statement.cpython-35.pyc b/ql/ast/nodes/statements/__pycache__/block_statement.cpython-35.pyc
new file mode 100644
index 0000000..8ec170d
--- /dev/null
+++ b/ql/ast/nodes/statements/__pycache__/block_statement.cpython-35.pyc
diff --git a/ql/ast/nodes/statements/__pycache__/form_statement.cpython-35.pyc b/ql/ast/nodes/statements/__pycache__/form_statement.cpython-35.pyc
new file mode 100644
index 0000000..e10775a
--- /dev/null
+++ b/ql/ast/nodes/statements/__pycache__/form_statement.cpython-35.pyc
diff --git a/ql/ast/nodes/statements/__pycache__/if_statement.cpython-35.pyc b/ql/ast/nodes/statements/__pycache__/if_statement.cpython-35.pyc
new file mode 100644
index 0000000..e81cfc1
--- /dev/null
+++ b/ql/ast/nodes/statements/__pycache__/if_statement.cpython-35.pyc
diff --git a/ql/ast/nodes/statements/__pycache__/question_statement.cpython-35.pyc b/ql/ast/nodes/statements/__pycache__/question_statement.cpython-35.pyc
new file mode 100644
index 0000000..6b86ed9
--- /dev/null
+++ b/ql/ast/nodes/statements/__pycache__/question_statement.cpython-35.pyc
diff --git a/ql/ast/nodes/statements/block_statement.py b/ql/ast/nodes/statements/block_statement.py
new file mode 100644
index 0000000..2013c82
--- /dev/null
+++ b/ql/ast/nodes/statements/block_statement.py
@@ -0,0 +1,11 @@
+from ql.ast.nodes.base import BaseNode
+
+
+class BlockStatementNode(BaseNode):
+    def __init__(self, metadata, block):
+        super(BlockStatementNode, self).__init__(metadata)
+        self.__block = block
+
+    @property
+    def block(self):
+        return self.__block
diff --git a/ql/ast/nodes/statements/form_statement.py b/ql/ast/nodes/statements/form_statement.py
new file mode 100644
index 0000000..0030623
--- /dev/null
+++ b/ql/ast/nodes/statements/form_statement.py
@@ -0,0 +1,12 @@
+from ql.ast.nodes.statements.block_statement import BlockStatementNode
+
+
+class FormNode(BlockStatementNode):
+    def __init__(self, metadata, block, identifier):
+        super(FormNode, self).__init__(metadata, block)
+        self.__identifier = identifier
+
+    @property
+    def identifier(self):
+        return self.__identifier
+
diff --git a/ql/ast/nodes/statements/if_statement.py b/ql/ast/nodes/statements/if_statement.py
new file mode 100644
index 0000000..68845b8
--- /dev/null
+++ b/ql/ast/nodes/statements/if_statement.py
@@ -0,0 +1,11 @@
+from ql.ast.nodes.statements.block_statement import BlockStatementNode
+
+
+class IfNode(BlockStatementNode):
+    def __init__(self, metadata, block, condition):
+        super(IfNode, self).__init__(metadata, block)
+        self.__condition = condition
+
+    @property
+    def condition(self):
+        return self.__condition
diff --git a/ql/ast/nodes/statements/question_statement.py b/ql/ast/nodes/statements/question_statement.py
new file mode 100644
index 0000000..2878449
--- /dev/null
+++ b/ql/ast/nodes/statements/question_statement.py
@@ -0,0 +1,31 @@
+from ql.ast.nodes.base import BaseNode
+
+
+class QuestionNode(BaseNode):
+    def __init__(self, line_number, label, identifier, answer_type, answer, computed):
+        super(QuestionNode, self).__init__(line_number)
+        self.__label = label
+        self.__identifier = identifier
+        self.__answer_type = answer_type
+        self.__answer = answer
+        self.__computed = computed
+
+    @property
+    def label(self):
+        return self.__label
+
+    @property
+    def identifier(self):
+        return self.__identifier
+
+    @property
+    def answer_type(self):
+        return self.__answer_type
+
+    @property
+    def answer(self):
+        return self.__answer
+
+    @property
+    def computed(self):
+        return self.__computed
diff --git a/ql/ast/visitors/__pycache__/dependency_visitor.cpython-35.pyc b/ql/ast/visitors/__pycache__/dependency_visitor.cpython-35.pyc
new file mode 100644
index 0000000..8d348e6
--- /dev/null
+++ b/ql/ast/visitors/__pycache__/dependency_visitor.cpython-35.pyc
diff --git a/ql/ast/visitors/__pycache__/expression_evaluator.cpython-35.pyc b/ql/ast/visitors/__pycache__/expression_evaluator.cpython-35.pyc
new file mode 100644
index 0000000..29a2e9b
--- /dev/null
+++ b/ql/ast/visitors/__pycache__/expression_evaluator.cpython-35.pyc
diff --git a/ql/ast/visitors/__pycache__/identifier_type_visitor.cpython-35.pyc b/ql/ast/visitors/__pycache__/identifier_type_visitor.cpython-35.pyc
new file mode 100644
index 0000000..89f690d
--- /dev/null
+++ b/ql/ast/visitors/__pycache__/identifier_type_visitor.cpython-35.pyc
diff --git a/ql/ast/visitors/__pycache__/model_generator.cpython-35.pyc b/ql/ast/visitors/__pycache__/model_generator.cpython-35.pyc
new file mode 100644
index 0000000..9950522
--- /dev/null
+++ b/ql/ast/visitors/__pycache__/model_generator.cpython-35.pyc
diff --git a/ql/ast/visitors/__pycache__/question_visitor.cpython-35.pyc b/ql/ast/visitors/__pycache__/question_visitor.cpython-35.pyc
new file mode 100644
index 0000000..ac60a13
--- /dev/null
+++ b/ql/ast/visitors/__pycache__/question_visitor.cpython-35.pyc
diff --git a/ql/ast/visitors/__pycache__/reference_visitor.cpython-35.pyc b/ql/ast/visitors/__pycache__/reference_visitor.cpython-35.pyc
new file mode 100644
index 0000000..e0491b9
--- /dev/null
+++ b/ql/ast/visitors/__pycache__/reference_visitor.cpython-35.pyc
diff --git a/ql/ast/visitors/__pycache__/type_visitor.cpython-35.pyc b/ql/ast/visitors/__pycache__/type_visitor.cpython-35.pyc
new file mode 100644
index 0000000..a2df3f2
--- /dev/null
+++ b/ql/ast/visitors/__pycache__/type_visitor.cpython-35.pyc
diff --git a/ql/ast/visitors/dependency_visitor.py b/ql/ast/visitors/dependency_visitor.py
new file mode 100644
index 0000000..8bb81eb
--- /dev/null
+++ b/ql/ast/visitors/dependency_visitor.py
@@ -0,0 +1,54 @@
+from multimethods import multimethod
+
+from ql.ast.nodes.expressions.binary_operators.binary_operator import BinaryOperatorNode
+from ql.ast.nodes.expressions.literals.literal import LiteralNode
+from ql.ast.nodes.expressions.unary_operators.unary_operator import UnaryOperatorNode
+from ql.ast.nodes.expressions.variable import VariableNode
+from ql.ast.nodes.statements.form_statement import FormNode
+from ql.ast.nodes.statements.if_statement import IfNode
+from ql.ast.nodes.statements.question_statement import QuestionNode
+
+
+class DependencyVisitor:
+    def __init__(self):
+        self.__all_dependencies = []
+        self.__current_dependencies = []
+
+    @property
+    def identifier_dependencies(self):
+        return self.__all_dependencies
+
+    @multimethod(FormNode)
+    def visit(self, node):
+        for child in node.block:
+            child.accept(self)
+
+    @multimethod(IfNode)
+    def visit(self, node):
+        node.condition.accept(self)
+        for child in node.block:
+            child.accept(self)
+
+    @multimethod(QuestionNode)
+    def visit(self, node):
+        if node.computed:
+            self.__current_dependencies = []
+            node.answer.accept(self)
+            self.__all_dependencies.append((node.identifier, self.__current_dependencies, node.metadata))
+
+    @multimethod(BinaryOperatorNode)
+    def visit(self, node):
+        node.left_expression.accept(self)
+        node.right_expression.accept(self)
+
+    @multimethod(UnaryOperatorNode)
+    def visit(self, node):
+        node.expression.accept(self)
+
+    @multimethod(VariableNode)
+    def visit(self, node):
+        self.__current_dependencies.append(node.identifier)
+
+    @multimethod(LiteralNode)
+    def visit(self, node):
+        pass
diff --git a/ql/ast/visitors/expression_evaluator.py b/ql/ast/visitors/expression_evaluator.py
new file mode 100644
index 0000000..9306d98
--- /dev/null
+++ b/ql/ast/visitors/expression_evaluator.py
@@ -0,0 +1,37 @@
+from multimethods import multimethod
+
+from ql.ast.nodes.expressions.binary_operators.binary_operator import BinaryOperatorNode
+from ql.ast.nodes.expressions.literals.literal import LiteralNode
+from ql.ast.nodes.expressions.unary_operators.unary_operator import UnaryOperatorNode
+from ql.ast.nodes.expressions.variable import VariableNode
+from ql.types.undefined import QLUndefined
+
+
+class ExpressionEvaluator:
+    def __init__(self, form):
+        self.form = form
+        self.result = QLUndefined()
+
+    @multimethod(BinaryOperatorNode)
+    def visit(self, node):
+        node.left_expression.accept(self)
+        node.right_expression.accept(self)
+        node.evaluate()
+        self.result = node.value
+
+    @multimethod(UnaryOperatorNode)
+    def visit(self, node):
+        node.expression.accept(self)
+        node.evaluate()
+        self.result = node.value
+
+    @multimethod(LiteralNode)
+    def visit(self, node):
+        self.result = node.value
+
+    @multimethod(VariableNode)
+    def visit(self, node):
+        for question in self.form.block:
+            if node.identifier == question.identifier:
+                node.value = question.answer.value
+                self.result = node.value
diff --git a/ql/ast/visitors/identifier_type_visitor.py b/ql/ast/visitors/identifier_type_visitor.py
new file mode 100644
index 0000000..d064f5b
--- /dev/null
+++ b/ql/ast/visitors/identifier_type_visitor.py
@@ -0,0 +1,31 @@
+from multimethods import multimethod
+
+from ql.ast.nodes.statements.form_statement import FormNode
+from ql.ast.nodes.statements.if_statement import IfNode
+from ql.ast.nodes.statements.question_statement import QuestionNode
+
+
+class IdentifierTypeVisitor:
+    def __init__(self):
+        self.__symbol_table = []
+
+    @property
+    def symbol_table(self):
+        return self.__symbol_table
+
+    @multimethod(FormNode)
+    def visit(self, node):
+        for child in node.block:
+            child.accept(self)
+
+    @multimethod(IfNode)
+    def visit(self, node):
+        for child in node.block:
+            child.accept(self)
+
+    @multimethod(QuestionNode)
+    def visit(self, node):
+        self.__symbol_table.append({
+            'identifier': node.identifier,
+            'answer_type': node.answer_type,
+        })
diff --git a/ql/ast/visitors/model_generator.py b/ql/ast/visitors/model_generator.py
new file mode 100644
index 0000000..f2cf5d8
--- /dev/null
+++ b/ql/ast/visitors/model_generator.py
@@ -0,0 +1,39 @@
+from multimethods import multimethod
+
+from gui.model.form import FormModel
+from gui.model.question import QuestionModel
+from ql.ast.nodes.expressions.binary_operators.and_operator import AndOperatorNode
+from ql.ast.nodes.statements.form_statement import FormNode
+from ql.ast.nodes.statements.if_statement import IfNode
+from ql.ast.nodes.statements.question_statement import QuestionNode
+from ql.types.boolean import QLBoolean
+from ql.types.undefined import QLUndefined
+
+
+class ModelGenerator:
+    def __init__(self):
+        self.form = None
+        self.condition = QLBoolean.get_literal_node(True)
+
+    @multimethod(FormNode)
+    def visit(self, node):
+        self.form = FormModel(node.identifier)
+
+        for child in node.block:
+            child.accept(self)
+
+    @multimethod(IfNode)
+    def visit(self, node):
+        previous_condition = self.condition
+        self.condition = AndOperatorNode(None, QLBoolean, self.condition, node.condition, QLUndefined())
+
+        for child in node.block:
+            child.accept(self)
+
+        self.condition = previous_condition
+
+    @multimethod(QuestionNode)
+    def visit(self, node):
+        question_model = QuestionModel(node.label, node.identifier, node.answer_type,
+                                       node.answer, node.computed, self.condition)
+        self.form.block.append(question_model)
diff --git a/ql/ast/visitors/question_visitor.py b/ql/ast/visitors/question_visitor.py
new file mode 100644
index 0000000..8037364
--- /dev/null
+++ b/ql/ast/visitors/question_visitor.py
@@ -0,0 +1,33 @@
+from multimethods import multimethod
+
+from ql.ast.nodes.statements.form_statement import FormNode
+from ql.ast.nodes.statements.if_statement import IfNode
+from ql.ast.nodes.statements.question_statement import QuestionNode
+
+
+class QuestionVisitor:
+    def __init__(self):
+        self.__questions = []
+
+    @property
+    def questions(self):
+        return self.__questions
+
+    @multimethod(FormNode)
+    def visit(self, node):
+        for child in node.block:
+            child.accept(self)
+
+    @multimethod(IfNode)
+    def visit(self, node):
+        for child in node.block:
+            child.accept(self)
+
+    @multimethod(QuestionNode)
+    def visit(self, node):
+        self.__questions.append({
+            'label': node.label,
+            'identifier': node.identifier,
+            'answer_type': node.answer_type,
+            'metadata': node.metadata,
+        })
diff --git a/ql/ast/visitors/reference_visitor.py b/ql/ast/visitors/reference_visitor.py
new file mode 100644
index 0000000..5cbbcc7
--- /dev/null
+++ b/ql/ast/visitors/reference_visitor.py
@@ -0,0 +1,86 @@
+from multimethods import multimethod
+
+from ql.ast.nodes.expressions.binary_operators.binary_operator import BinaryOperatorNode
+from ql.ast.nodes.expressions.literals.literal import LiteralNode
+from ql.ast.nodes.expressions.unary_operators.unary_operator import UnaryOperatorNode
+from ql.ast.nodes.expressions.variable import VariableNode
+from ql.ast.nodes.statements.form_statement import FormNode
+from ql.ast.nodes.statements.if_statement import IfNode
+from ql.ast.nodes.statements.question_statement import QuestionNode
+
+
+class ReferenceVisitor:
+    def __init__(self):
+        self.__current_block = []
+        self.__current_scope = {}
+
+    @property
+    def identifier_scopes(self):
+        return self.__current_scope
+
+    @multimethod(FormNode)
+    def visit(self, node):
+        self.__current_scope = {
+            'content':  [],
+            'children': [],
+        }
+        self.__current_block = []
+
+        for child in node.block:
+            child.accept(self)
+
+        self.__current_scope['content'] = self.__current_block
+
+    @multimethod(IfNode)
+    def visit(self, node):
+        node.condition.accept(self)
+
+        self.__current_scope['content'] += self.__current_block
+        previous_scope = self.__current_scope
+        previous_block = self.__current_block
+        self.__current_block = []
+        self.__current_scope = {
+            'content':  [],
+            'children': [],
+        }
+
+        for child in node.block:
+            child.accept(self)
+
+        self.__current_scope['content'] = self.__current_block
+        previous_scope['children'].append(self.__current_scope)
+        self.__current_block = previous_block
+        self.__current_scope = previous_scope
+
+    @multimethod(QuestionNode)
+    def visit(self, node):
+        self.__current_block.append(dict({
+            'name': node.identifier,
+            'type': node.answer_type,
+            'line': node.metadata.line,
+        }))
+
+        if node.computed:
+            node.answer.accept(self)
+
+    @multimethod(BinaryOperatorNode)
+    def visit(self, node):
+        node.left_expression.accept(self)
+        node.right_expression.accept(self)
+
+    @multimethod(UnaryOperatorNode)
+    def visit(self, node):
+        node.expression.accept(self)
+
+    @multimethod(VariableNode)
+    def visit(self, node):
+        name = node.identifier
+        self.__current_block.append({
+            'name': name,
+            'type': [],
+            'line': node.metadata.line,
+        })
+
+    @multimethod(LiteralNode)
+    def visit(self, node):
+        pass
diff --git a/ql/ast/visitors/type_visitor.py b/ql/ast/visitors/type_visitor.py
new file mode 100644
index 0000000..7f4ac7c
--- /dev/null
+++ b/ql/ast/visitors/type_visitor.py
@@ -0,0 +1,85 @@
+from multimethods import multimethod
+
+from ql.ast.nodes.expressions.binary_operators.binary_operator import BinaryOperatorNode
+from ql.ast.nodes.expressions.literals.literal import LiteralNode
+from ql.ast.nodes.expressions.unary_operators.unary_operator import UnaryOperatorNode
+from ql.ast.nodes.expressions.variable import VariableNode
+from ql.ast.nodes.statements.form_statement import FormNode
+from ql.ast.nodes.statements.if_statement import IfNode
+from ql.ast.nodes.statements.question_statement import QuestionNode
+from ql.types.boolean import QLBoolean
+from ql.types.undefined import QLUndefined
+
+
+class TypeVisitor:
+    def __init__(self, symbol_table):
+        self.__symbol_table = symbol_table
+        self.__errors = []
+
+    @property
+    def errors(self):
+        return self.__errors
+
+    @multimethod(FormNode)
+    def visit(self, node):
+        for child in node.block:
+            child.accept(self)
+
+    @multimethod(IfNode)
+    def visit(self, node):
+        node.condition.accept(self)
+
+        if node.condition.expression_type != QLBoolean:
+            self.__errors.append('Condition does not evaluate to boolean on line {}.'
+                                 .format(node.metadata.line))
+
+        for child in node.block:
+            child.accept(self)
+
+    @multimethod(QuestionNode)
+    def visit(self, node):
+        if node.computed:
+            node.answer.accept(self)
+
+            result_type = node.answer.expression_type
+
+            if node.answer_type != result_type:
+                self.__errors.append('Expression not of type {} on line {}'
+                                     .format(node.answer_type, node.answer.metadata.line))
+
+    @multimethod(BinaryOperatorNode)
+    def visit(self, node):
+        node.left_expression.accept(self)
+        node.right_expression.accept(self)
+
+        result_type = node.get_result_type()
+
+        if result_type == QLUndefined:
+            self.__errors.append('Invalid operands: {} and {} not supported for binary operation on line {}'
+                                 .format(node.left_expression.expression_type,
+                                         node.right_expression.expression_type,
+                                         node.metadata.line))
+
+        node.expression_type = result_type
+
+    @multimethod(UnaryOperatorNode)
+    def visit(self, node):
+        node.expression.accept(self)
+
+        result_type = node.get_result_type()
+
+        if result_type == QLUndefined:
+            self.__errors.append('Invalid operand: {} not supported for unary operation on line {}'
+                                 .format(node.expression.expression_type, node.metadata.line))
+
+        node.expression_type = result_type
+
+    @multimethod(VariableNode)
+    def visit(self, node):
+        for row in self.__symbol_table:
+            if row['identifier'] == node.identifier:
+                node.expression_type = row['answer_type']
+
+    @multimethod(LiteralNode)
+    def visit(self, node):
+        pass
diff --git a/ql/parser/__pycache__/lexer.cpython-35.pyc b/ql/parser/__pycache__/lexer.cpython-35.pyc
new file mode 100644
index 0000000..f2d9220
--- /dev/null
+++ b/ql/parser/__pycache__/lexer.cpython-35.pyc
diff --git a/ql/parser/__pycache__/metadata.cpython-35.pyc b/ql/parser/__pycache__/metadata.cpython-35.pyc
new file mode 100644
index 0000000..0f1f298
--- /dev/null
+++ b/ql/parser/__pycache__/metadata.cpython-35.pyc
diff --git a/ql/parser/__pycache__/parser.cpython-35.pyc b/ql/parser/__pycache__/parser.cpython-35.pyc
new file mode 100644
index 0000000..6eb96b9
--- /dev/null
+++ b/ql/parser/__pycache__/parser.cpython-35.pyc
diff --git a/ql/parser/__pycache__/parsetab.cpython-35.pyc b/ql/parser/__pycache__/parsetab.cpython-35.pyc
new file mode 100644
index 0000000..bd4db77
--- /dev/null
+++ b/ql/parser/__pycache__/parsetab.cpython-35.pyc
diff --git a/ql/parser/lexer.py b/ql/parser/lexer.py
new file mode 100644
index 0000000..6e53f12
--- /dev/null
+++ b/ql/parser/lexer.py
@@ -0,0 +1,153 @@
+from re import findall

+

+from ply.lex import lex

+

+

+class QLLexer:

+    def __init__(self):

+        self.__errors = []

+        self.__lexer = None

+

+    @property

+    def lexer(self):

+        return self.__lexer

+

+    @property

+    def errors(self):

+        return self.__errors

+

+    def build(self):

+        self.__lexer = lex(module=self)

+

+    def tokenize(self, data):

+        self.__errors = []

+        self.lexer.input(data)

+        token = self.lexer.token()

+        tokens = [token]

+

+        while token:

+            token = self.lexer.token()

+            tokens.append(token)

+

+        return tokens

+

+    tokens = [

+        'PLUS', 'MINUS', 'TIMES', 'DIVIDE', 'COLON',

+        'ASSIGN',

+        'EQUALS', 'NOT_EQUALS',

+        'LESS_EQUALS', 'LESS_THAN', 'GREATER_EQUALS', 'GREATER_THAN',

+        'AND', 'OR',

+        'DOLLAR', 'RUBLE',

+        'LEFT_BRACE', 'RIGHT_BRACE',

+        'LEFT_BRACKET', 'RIGHT_BRACKET',

+        'INTEGER_LITERAL', 'DECIMAL_LITERAL',

+        'TRUE', 'FALSE',

+        'DATE_LITERAL',

+        'STRING_LITERAL',

+        'IDENTIFIER',

+    ]

+

+    reserved_keywords = {

+        'form':     'FORM',

+        'if':       'IF',

+        'not':      'NOT',

+

+        # Types

+        'boolean':  'BOOLEAN',

+        'date':     'DATE',

+        'decimal':  'DECIMAL',

+        'integer':  'INTEGER',

+        'money':    'MONEY',

+        'string':   'STRING',

+    }

+

+    tokens += list(reserved_keywords.values())

+

+    # Regular expression rules for simple tokens

+    t_ignore = ' \t'

+

+    t_PLUS = r'\+'

+    t_MINUS = r'-'

+    t_TIMES = r'\*'

+    t_DIVIDE = r'/'

+    t_COLON = r':'

+    t_ASSIGN = r'='

+

+    t_LESS_EQUALS = r'<='

+    t_LESS_THAN = r'<'

+    t_GREATER_EQUALS = r'>='

+    t_GREATER_THAN = r'>'

+    t_EQUALS = r'=='

+    t_NOT_EQUALS = r'!='

+    t_AND = r'&&'

+    t_OR = r'\|\|'

+

+    t_DOLLAR = r'\$'

+    t_RUBLE = r'\₽'

+

+    t_LEFT_BRACE = r'\{'

+    t_RIGHT_BRACE = r'\}'

+

+    t_LEFT_BRACKET = r'\('

+    t_RIGHT_BRACKET = r'\)'

+

+    # Literals

+    @staticmethod

+    def t_FALSE(token):

+        r'False'

+        token.value = False

+        return token

+

+    @staticmethod

+    def t_TRUE(token):

+        r'True'

+        token.value = True

+        return token

+

+    def t_DATE_LITERAL(self, token):

+        r'date\(\s*\d{1,2}\s*,\s*\d{1,2}\s*,\s*\d{1,4}\s*\)'

+

+        try:

+            token.value = findall(r'\d\d*', token.value)

+            return token

+        except SyntaxError:

+            self.errors.append('Invalid date.')

+

+    @staticmethod

+    def t_DECIMAL_LITERAL(token):

+        r'\d+[.]\d+'

+        token.value = token.value

+        return token

+

+    @staticmethod

+    def t_INTEGER_LITERAL(token):

+        r'\d+'

+        token.value = token.value

+        return token

+

+    @staticmethod

+    def t_STRING_LITERAL(token):

+        r'\"(.+?)\"'

+        token.value = token.value[1:-1]

+        return token

+

+    # Other

+    def t_IDENTIFIER(self, token):

+        r'[a-z][a-zA-Z_0-9]*'

+        token.type = self.reserved_keywords.get(token.value, 'IDENTIFIER')

+        return token

+

+    @staticmethod

+    def t_comment(token):

+        r'//.*'

+        pass

+

+    @staticmethod

+    def t_newline(token):

+        r'\n+'

+        token.lexer.lineno += len(token.value)

+

+    # Error handling

+    def t_error(self, token):

+        self.errors.append("Illegal character '%s'" % token.value[0])

+        token.lexer.skip(1)

diff --git a/ql/parser/metadata.py b/ql/parser/metadata.py
new file mode 100644
index 0000000..618b4ba
--- /dev/null
+++ b/ql/parser/metadata.py
@@ -0,0 +1,7 @@
+class Metadata:
+    def __init__(self, line):
+        self.__line = line
+
+    @property
+    def line(self):
+        return self.__line
diff --git a/ql/parser/parser.out b/ql/parser/parser.out
new file mode 100644
index 0000000..e1a1452
--- /dev/null
+++ b/ql/parser/parser.out
@@ -0,0 +1,2214 @@
+Created by PLY version 3.11 (http://www.dabeaz.com/ply)
+
+Grammar
+
+Rule 0     S' -> form
+Rule 1     form -> FORM IDENTIFIER block
+Rule 2     block -> LEFT_BRACE statements RIGHT_BRACE
+Rule 3     statements -> statement statements
+Rule 4     statements -> statement
+Rule 5     statement -> if
+Rule 6     statement -> question
+Rule 7     question -> STRING_LITERAL IDENTIFIER COLON type
+Rule 8     question -> STRING_LITERAL IDENTIFIER COLON type ASSIGN expression
+Rule 9     if -> IF condition block
+Rule 10    condition -> LEFT_BRACKET expression RIGHT_BRACKET
+Rule 11    expression -> LEFT_BRACKET expression RIGHT_BRACKET
+Rule 12    expression -> IDENTIFIER
+Rule 13    expression -> NOT expression
+Rule 14    expression -> MINUS expression
+Rule 15    expression -> expression AND expression
+Rule 16    expression -> expression OR expression
+Rule 17    expression -> expression PLUS expression
+Rule 18    expression -> expression MINUS expression
+Rule 19    expression -> expression TIMES expression
+Rule 20    expression -> expression DIVIDE expression
+Rule 21    expression -> expression EQUALS expression
+Rule 22    expression -> expression NOT_EQUALS expression
+Rule 23    expression -> expression LESS_EQUALS expression
+Rule 24    expression -> expression LESS_THAN expression
+Rule 25    expression -> expression GREATER_EQUALS expression
+Rule 26    expression -> expression GREATER_THAN expression
+Rule 27    expression -> FALSE
+Rule 28    expression -> TRUE
+Rule 29    expression -> DATE_LITERAL
+Rule 30    expression -> INTEGER_LITERAL
+Rule 31    expression -> DECIMAL_LITERAL
+Rule 32    expression -> currency DECIMAL_LITERAL
+Rule 33    expression -> currency INTEGER_LITERAL
+Rule 34    expression -> STRING_LITERAL
+Rule 35    currency -> DOLLAR
+Rule 36    currency -> RUBLE
+Rule 37    type -> BOOLEAN
+Rule 38    type -> DECIMAL
+Rule 39    type -> STRING
+Rule 40    type -> DATE
+Rule 41    type -> MONEY
+Rule 42    type -> INTEGER
+Rule 43    form -> FORM LEFT_BRACE
+Rule 44    form -> FORM IDENTIFIER LEFT_BRACE RIGHT_BRACE
+Rule 45    statement -> IF condition LEFT_BRACE RIGHT_BRACE
+Rule 46    condition -> LEFT_BRACKET RIGHT_BRACKET
+
+Terminals, with rules where they appear
+
+AND                  : 15
+ASSIGN               : 8
+BOOLEAN              : 37
+COLON                : 7 8
+DATE                 : 40
+DATE_LITERAL         : 29
+DECIMAL              : 38
+DECIMAL_LITERAL      : 31 32
+DIVIDE               : 20
+DOLLAR               : 35
+EQUALS               : 21
+FALSE                : 27
+FORM                 : 1 43 44
+GREATER_EQUALS       : 25
+GREATER_THAN         : 26
+IDENTIFIER           : 1 7 8 12 44
+IF                   : 9 45
+INTEGER              : 42
+INTEGER_LITERAL      : 30 33
+LEFT_BRACE           : 2 43 44 45
+LEFT_BRACKET         : 10 11 46
+LESS_EQUALS          : 23
+LESS_THAN            : 24
+MINUS                : 14 18
+MONEY                : 41
+NOT                  : 13
+NOT_EQUALS           : 22
+OR                   : 16
+PLUS                 : 17
+RIGHT_BRACE          : 2 44 45
+RIGHT_BRACKET        : 10 11 46
+RUBLE                : 36
+STRING               : 39
+STRING_LITERAL       : 7 8 34
+TIMES                : 19
+TRUE                 : 28
+error                : 
+
+Nonterminals, with rules where they appear
+
+block                : 1 9
+condition            : 9 45
+currency             : 32 33
+expression           : 8 10 11 13 14 15 15 16 16 17 17 18 18 19 19 20 20 21 21 22 22 23 23 24 24 25 25 26 26
+form                 : 0
+if                   : 5
+question             : 6
+statement            : 3 4
+statements           : 2 3
+type                 : 7 8
+
+Parsing method: LALR
+
+state 0
+
+    (0) S' -> . form
+    (1) form -> . FORM IDENTIFIER block
+    (43) form -> . FORM LEFT_BRACE
+    (44) form -> . FORM IDENTIFIER LEFT_BRACE RIGHT_BRACE
+
+    FORM            shift and go to state 1
+
+    form                           shift and go to state 2
+
+state 1
+
+    (1) form -> FORM . IDENTIFIER block
+    (43) form -> FORM . LEFT_BRACE
+    (44) form -> FORM . IDENTIFIER LEFT_BRACE RIGHT_BRACE
+
+    IDENTIFIER      shift and go to state 3
+    LEFT_BRACE      shift and go to state 4
+
+
+state 2
+
+    (0) S' -> form .
+
+
+
+state 3
+
+    (1) form -> FORM IDENTIFIER . block
+    (44) form -> FORM IDENTIFIER . LEFT_BRACE RIGHT_BRACE
+    (2) block -> . LEFT_BRACE statements RIGHT_BRACE
+
+    LEFT_BRACE      shift and go to state 5
+
+    block                          shift and go to state 6
+
+state 4
+
+    (43) form -> FORM LEFT_BRACE .
+
+    $end            reduce using rule 43 (form -> FORM LEFT_BRACE .)
+
+
+state 5
+
+    (44) form -> FORM IDENTIFIER LEFT_BRACE . RIGHT_BRACE
+    (2) block -> LEFT_BRACE . statements RIGHT_BRACE
+    (3) statements -> . statement statements
+    (4) statements -> . statement
+    (5) statement -> . if
+    (6) statement -> . question
+    (45) statement -> . IF condition LEFT_BRACE RIGHT_BRACE
+    (9) if -> . IF condition block
+    (7) question -> . STRING_LITERAL IDENTIFIER COLON type
+    (8) question -> . STRING_LITERAL IDENTIFIER COLON type ASSIGN expression
+
+    RIGHT_BRACE     shift and go to state 13
+    IF              shift and go to state 11
+    STRING_LITERAL  shift and go to state 12
+
+    if                             shift and go to state 7
+    question                       shift and go to state 8
+    statements                     shift and go to state 9
+    statement                      shift and go to state 10
+
+state 6
+
+    (1) form -> FORM IDENTIFIER block .
+
+    $end            reduce using rule 1 (form -> FORM IDENTIFIER block .)
+
+
+state 7
+
+    (5) statement -> if .
+
+    IF              reduce using rule 5 (statement -> if .)
+    STRING_LITERAL  reduce using rule 5 (statement -> if .)
+    RIGHT_BRACE     reduce using rule 5 (statement -> if .)
+
+
+state 8
+
+    (6) statement -> question .
+
+    IF              reduce using rule 6 (statement -> question .)
+    STRING_LITERAL  reduce using rule 6 (statement -> question .)
+    RIGHT_BRACE     reduce using rule 6 (statement -> question .)
+
+
+state 9
+
+    (2) block -> LEFT_BRACE statements . RIGHT_BRACE
+
+    RIGHT_BRACE     shift and go to state 14
+
+
+state 10
+
+    (3) statements -> statement . statements
+    (4) statements -> statement .
+    (3) statements -> . statement statements
+    (4) statements -> . statement
+    (5) statement -> . if
+    (6) statement -> . question
+    (45) statement -> . IF condition LEFT_BRACE RIGHT_BRACE
+    (9) if -> . IF condition block
+    (7) question -> . STRING_LITERAL IDENTIFIER COLON type
+    (8) question -> . STRING_LITERAL IDENTIFIER COLON type ASSIGN expression
+
+    RIGHT_BRACE     reduce using rule 4 (statements -> statement .)
+    IF              shift and go to state 11
+    STRING_LITERAL  shift and go to state 12
+
+    if                             shift and go to state 7
+    question                       shift and go to state 8
+    statements                     shift and go to state 15
+    statement                      shift and go to state 10
+
+state 11
+
+    (45) statement -> IF . condition LEFT_BRACE RIGHT_BRACE
+    (9) if -> IF . condition block
+    (10) condition -> . LEFT_BRACKET expression RIGHT_BRACKET
+    (46) condition -> . LEFT_BRACKET RIGHT_BRACKET
+
+    LEFT_BRACKET    shift and go to state 17
+
+    condition                      shift and go to state 16
+
+state 12
+
+    (7) question -> STRING_LITERAL . IDENTIFIER COLON type
+    (8) question -> STRING_LITERAL . IDENTIFIER COLON type ASSIGN expression
+
+    IDENTIFIER      shift and go to state 18
+
+
+state 13
+
+    (44) form -> FORM IDENTIFIER LEFT_BRACE RIGHT_BRACE .
+
+    $end            reduce using rule 44 (form -> FORM IDENTIFIER LEFT_BRACE RIGHT_BRACE .)
+
+
+state 14
+
+    (2) block -> LEFT_BRACE statements RIGHT_BRACE .
+
+    IF              reduce using rule 2 (block -> LEFT_BRACE statements RIGHT_BRACE .)
+    STRING_LITERAL  reduce using rule 2 (block -> LEFT_BRACE statements RIGHT_BRACE .)
+    RIGHT_BRACE     reduce using rule 2 (block -> LEFT_BRACE statements RIGHT_BRACE .)
+    $end            reduce using rule 2 (block -> LEFT_BRACE statements RIGHT_BRACE .)
+
+
+state 15
+
+    (3) statements -> statement statements .
+
+    RIGHT_BRACE     reduce using rule 3 (statements -> statement statements .)
+
+
+state 16
+
+    (45) statement -> IF condition . LEFT_BRACE RIGHT_BRACE
+    (9) if -> IF condition . block
+    (2) block -> . LEFT_BRACE statements RIGHT_BRACE
+
+    LEFT_BRACE      shift and go to state 19
+
+    block                          shift and go to state 20
+
+state 17
+
+    (10) condition -> LEFT_BRACKET . expression RIGHT_BRACKET
+    (46) condition -> LEFT_BRACKET . RIGHT_BRACKET
+    (11) expression -> . LEFT_BRACKET expression RIGHT_BRACKET
+    (12) expression -> . IDENTIFIER
+    (13) expression -> . NOT expression
+    (14) expression -> . MINUS expression
+    (15) expression -> . expression AND expression
+    (16) expression -> . expression OR expression
+    (17) expression -> . expression PLUS expression
+    (18) expression -> . expression MINUS expression
+    (19) expression -> . expression TIMES expression
+    (20) expression -> . expression DIVIDE expression
+    (21) expression -> . expression EQUALS expression
+    (22) expression -> . expression NOT_EQUALS expression
+    (23) expression -> . expression LESS_EQUALS expression
+    (24) expression -> . expression LESS_THAN expression
+    (25) expression -> . expression GREATER_EQUALS expression
+    (26) expression -> . expression GREATER_THAN expression
+    (27) expression -> . FALSE
+    (28) expression -> . TRUE
+    (29) expression -> . DATE_LITERAL
+    (30) expression -> . INTEGER_LITERAL
+    (31) expression -> . DECIMAL_LITERAL
+    (32) expression -> . currency DECIMAL_LITERAL
+    (33) expression -> . currency INTEGER_LITERAL
+    (34) expression -> . STRING_LITERAL
+    (35) currency -> . DOLLAR
+    (36) currency -> . RUBLE
+
+    RIGHT_BRACKET   shift and go to state 21
+    LEFT_BRACKET    shift and go to state 30
+    IDENTIFIER      shift and go to state 34
+    NOT             shift and go to state 27
+    MINUS           shift and go to state 25
+    FALSE           shift and go to state 35
+    TRUE            shift and go to state 32
+    DATE_LITERAL    shift and go to state 24
+    INTEGER_LITERAL shift and go to state 26
+    DECIMAL_LITERAL shift and go to state 31
+    STRING_LITERAL  shift and go to state 28
+    DOLLAR          shift and go to state 29
+    RUBLE           shift and go to state 23
+
+    currency                       shift and go to state 22
+    expression                     shift and go to state 33
+
+state 18
+
+    (7) question -> STRING_LITERAL IDENTIFIER . COLON type
+    (8) question -> STRING_LITERAL IDENTIFIER . COLON type ASSIGN expression
+
+    COLON           shift and go to state 36
+
+
+state 19
+
+    (45) statement -> IF condition LEFT_BRACE . RIGHT_BRACE
+    (2) block -> LEFT_BRACE . statements RIGHT_BRACE
+    (3) statements -> . statement statements
+    (4) statements -> . statement
+    (5) statement -> . if
+    (6) statement -> . question
+    (45) statement -> . IF condition LEFT_BRACE RIGHT_BRACE
+    (9) if -> . IF condition block
+    (7) question -> . STRING_LITERAL IDENTIFIER COLON type
+    (8) question -> . STRING_LITERAL IDENTIFIER COLON type ASSIGN expression
+
+    RIGHT_BRACE     shift and go to state 37
+    IF              shift and go to state 11
+    STRING_LITERAL  shift and go to state 12
+
+    if                             shift and go to state 7
+    question                       shift and go to state 8
+    statements                     shift and go to state 9
+    statement                      shift and go to state 10
+
+state 20
+
+    (9) if -> IF condition block .
+
+    IF              reduce using rule 9 (if -> IF condition block .)
+    STRING_LITERAL  reduce using rule 9 (if -> IF condition block .)
+    RIGHT_BRACE     reduce using rule 9 (if -> IF condition block .)
+
+
+state 21
+
+    (46) condition -> LEFT_BRACKET RIGHT_BRACKET .
+
+    LEFT_BRACE      reduce using rule 46 (condition -> LEFT_BRACKET RIGHT_BRACKET .)
+
+
+state 22
+
+    (32) expression -> currency . DECIMAL_LITERAL
+    (33) expression -> currency . INTEGER_LITERAL
+
+    DECIMAL_LITERAL shift and go to state 38
+    INTEGER_LITERAL shift and go to state 39
+
+
+state 23
+
+    (36) currency -> RUBLE .
+
+    DECIMAL_LITERAL reduce using rule 36 (currency -> RUBLE .)
+    INTEGER_LITERAL reduce using rule 36 (currency -> RUBLE .)
+
+
+state 24
+
+    (29) expression -> DATE_LITERAL .
+
+    AND             reduce using rule 29 (expression -> DATE_LITERAL .)
+    OR              reduce using rule 29 (expression -> DATE_LITERAL .)
+    PLUS            reduce using rule 29 (expression -> DATE_LITERAL .)
+    MINUS           reduce using rule 29 (expression -> DATE_LITERAL .)
+    TIMES           reduce using rule 29 (expression -> DATE_LITERAL .)
+    DIVIDE          reduce using rule 29 (expression -> DATE_LITERAL .)
+    EQUALS          reduce using rule 29 (expression -> DATE_LITERAL .)
+    NOT_EQUALS      reduce using rule 29 (expression -> DATE_LITERAL .)
+    LESS_EQUALS     reduce using rule 29 (expression -> DATE_LITERAL .)
+    LESS_THAN       reduce using rule 29 (expression -> DATE_LITERAL .)
+    GREATER_EQUALS  reduce using rule 29 (expression -> DATE_LITERAL .)
+    GREATER_THAN    reduce using rule 29 (expression -> DATE_LITERAL .)
+    IF              reduce using rule 29 (expression -> DATE_LITERAL .)
+    STRING_LITERAL  reduce using rule 29 (expression -> DATE_LITERAL .)
+    RIGHT_BRACE     reduce using rule 29 (expression -> DATE_LITERAL .)
+    RIGHT_BRACKET   reduce using rule 29 (expression -> DATE_LITERAL .)
+
+
+state 25
+
+    (14) expression -> MINUS . expression
+    (11) expression -> . LEFT_BRACKET expression RIGHT_BRACKET
+    (12) expression -> . IDENTIFIER
+    (13) expression -> . NOT expression
+    (14) expression -> . MINUS expression
+    (15) expression -> . expression AND expression
+    (16) expression -> . expression OR expression
+    (17) expression -> . expression PLUS expression
+    (18) expression -> . expression MINUS expression
+    (19) expression -> . expression TIMES expression
+    (20) expression -> . expression DIVIDE expression
+    (21) expression -> . expression EQUALS expression
+    (22) expression -> . expression NOT_EQUALS expression
+    (23) expression -> . expression LESS_EQUALS expression
+    (24) expression -> . expression LESS_THAN expression
+    (25) expression -> . expression GREATER_EQUALS expression
+    (26) expression -> . expression GREATER_THAN expression
+    (27) expression -> . FALSE
+    (28) expression -> . TRUE
+    (29) expression -> . DATE_LITERAL
+    (30) expression -> . INTEGER_LITERAL
+    (31) expression -> . DECIMAL_LITERAL
+    (32) expression -> . currency DECIMAL_LITERAL
+    (33) expression -> . currency INTEGER_LITERAL
+    (34) expression -> . STRING_LITERAL
+    (35) currency -> . DOLLAR
+    (36) currency -> . RUBLE
+
+    LEFT_BRACKET    shift and go to state 30
+    IDENTIFIER      shift and go to state 34
+    NOT             shift and go to state 27
+    MINUS           shift and go to state 25
+    FALSE           shift and go to state 35
+    TRUE            shift and go to state 32
+    DATE_LITERAL    shift and go to state 24
+    INTEGER_LITERAL shift and go to state 26
+    DECIMAL_LITERAL shift and go to state 31
+    STRING_LITERAL  shift and go to state 28
+    DOLLAR          shift and go to state 29
+    RUBLE           shift and go to state 23
+
+    currency                       shift and go to state 22
+    expression                     shift and go to state 40
+
+state 26
+
+    (30) expression -> INTEGER_LITERAL .
+
+    AND             reduce using rule 30 (expression -> INTEGER_LITERAL .)
+    OR              reduce using rule 30 (expression -> INTEGER_LITERAL .)
+    PLUS            reduce using rule 30 (expression -> INTEGER_LITERAL .)
+    MINUS           reduce using rule 30 (expression -> INTEGER_LITERAL .)
+    TIMES           reduce using rule 30 (expression -> INTEGER_LITERAL .)
+    DIVIDE          reduce using rule 30 (expression -> INTEGER_LITERAL .)
+    EQUALS          reduce using rule 30 (expression -> INTEGER_LITERAL .)
+    NOT_EQUALS      reduce using rule 30 (expression -> INTEGER_LITERAL .)
+    LESS_EQUALS     reduce using rule 30 (expression -> INTEGER_LITERAL .)
+    LESS_THAN       reduce using rule 30 (expression -> INTEGER_LITERAL .)
+    GREATER_EQUALS  reduce using rule 30 (expression -> INTEGER_LITERAL .)
+    GREATER_THAN    reduce using rule 30 (expression -> INTEGER_LITERAL .)
+    IF              reduce using rule 30 (expression -> INTEGER_LITERAL .)
+    STRING_LITERAL  reduce using rule 30 (expression -> INTEGER_LITERAL .)
+    RIGHT_BRACE     reduce using rule 30 (expression -> INTEGER_LITERAL .)
+    RIGHT_BRACKET   reduce using rule 30 (expression -> INTEGER_LITERAL .)
+
+
+state 27
+
+    (13) expression -> NOT . expression
+    (11) expression -> . LEFT_BRACKET expression RIGHT_BRACKET
+    (12) expression -> . IDENTIFIER
+    (13) expression -> . NOT expression
+    (14) expression -> . MINUS expression
+    (15) expression -> . expression AND expression
+    (16) expression -> . expression OR expression
+    (17) expression -> . expression PLUS expression
+    (18) expression -> . expression MINUS expression
+    (19) expression -> . expression TIMES expression
+    (20) expression -> . expression DIVIDE expression
+    (21) expression -> . expression EQUALS expression
+    (22) expression -> . expression NOT_EQUALS expression
+    (23) expression -> . expression LESS_EQUALS expression
+    (24) expression -> . expression LESS_THAN expression
+    (25) expression -> . expression GREATER_EQUALS expression
+    (26) expression -> . expression GREATER_THAN expression
+    (27) expression -> . FALSE
+    (28) expression -> . TRUE
+    (29) expression -> . DATE_LITERAL
+    (30) expression -> . INTEGER_LITERAL
+    (31) expression -> . DECIMAL_LITERAL
+    (32) expression -> . currency DECIMAL_LITERAL
+    (33) expression -> . currency INTEGER_LITERAL
+    (34) expression -> . STRING_LITERAL
+    (35) currency -> . DOLLAR
+    (36) currency -> . RUBLE
+
+    LEFT_BRACKET    shift and go to state 30
+    IDENTIFIER      shift and go to state 34
+    NOT             shift and go to state 27
+    MINUS           shift and go to state 25
+    FALSE           shift and go to state 35
+    TRUE            shift and go to state 32
+    DATE_LITERAL    shift and go to state 24
+    INTEGER_LITERAL shift and go to state 26
+    DECIMAL_LITERAL shift and go to state 31
+    STRING_LITERAL  shift and go to state 28
+    DOLLAR          shift and go to state 29
+    RUBLE           shift and go to state 23
+
+    currency                       shift and go to state 22
+    expression                     shift and go to state 41
+
+state 28
+
+    (34) expression -> STRING_LITERAL .
+
+    AND             reduce using rule 34 (expression -> STRING_LITERAL .)
+    OR              reduce using rule 34 (expression -> STRING_LITERAL .)
+    PLUS            reduce using rule 34 (expression -> STRING_LITERAL .)
+    MINUS           reduce using rule 34 (expression -> STRING_LITERAL .)
+    TIMES           reduce using rule 34 (expression -> STRING_LITERAL .)
+    DIVIDE          reduce using rule 34 (expression -> STRING_LITERAL .)
+    EQUALS          reduce using rule 34 (expression -> STRING_LITERAL .)
+    NOT_EQUALS      reduce using rule 34 (expression -> STRING_LITERAL .)
+    LESS_EQUALS     reduce using rule 34 (expression -> STRING_LITERAL .)
+    LESS_THAN       reduce using rule 34 (expression -> STRING_LITERAL .)
+    GREATER_EQUALS  reduce using rule 34 (expression -> STRING_LITERAL .)
+    GREATER_THAN    reduce using rule 34 (expression -> STRING_LITERAL .)
+    IF              reduce using rule 34 (expression -> STRING_LITERAL .)
+    STRING_LITERAL  reduce using rule 34 (expression -> STRING_LITERAL .)
+    RIGHT_BRACE     reduce using rule 34 (expression -> STRING_LITERAL .)
+    RIGHT_BRACKET   reduce using rule 34 (expression -> STRING_LITERAL .)
+
+
+state 29
+
+    (35) currency -> DOLLAR .
+
+    DECIMAL_LITERAL reduce using rule 35 (currency -> DOLLAR .)
+    INTEGER_LITERAL reduce using rule 35 (currency -> DOLLAR .)
+
+
+state 30
+
+    (11) expression -> LEFT_BRACKET . expression RIGHT_BRACKET
+    (11) expression -> . LEFT_BRACKET expression RIGHT_BRACKET
+    (12) expression -> . IDENTIFIER
+    (13) expression -> . NOT expression
+    (14) expression -> . MINUS expression
+    (15) expression -> . expression AND expression
+    (16) expression -> . expression OR expression
+    (17) expression -> . expression PLUS expression
+    (18) expression -> . expression MINUS expression
+    (19) expression -> . expression TIMES expression
+    (20) expression -> . expression DIVIDE expression
+    (21) expression -> . expression EQUALS expression
+    (22) expression -> . expression NOT_EQUALS expression
+    (23) expression -> . expression LESS_EQUALS expression
+    (24) expression -> . expression LESS_THAN expression
+    (25) expression -> . expression GREATER_EQUALS expression
+    (26) expression -> . expression GREATER_THAN expression
+    (27) expression -> . FALSE
+    (28) expression -> . TRUE
+    (29) expression -> . DATE_LITERAL
+    (30) expression -> . INTEGER_LITERAL
+    (31) expression -> . DECIMAL_LITERAL
+    (32) expression -> . currency DECIMAL_LITERAL
+    (33) expression -> . currency INTEGER_LITERAL
+    (34) expression -> . STRING_LITERAL
+    (35) currency -> . DOLLAR
+    (36) currency -> . RUBLE
+
+    LEFT_BRACKET    shift and go to state 30
+    IDENTIFIER      shift and go to state 34
+    NOT             shift and go to state 27
+    MINUS           shift and go to state 25
+    FALSE           shift and go to state 35
+    TRUE            shift and go to state 32
+    DATE_LITERAL    shift and go to state 24
+    INTEGER_LITERAL shift and go to state 26
+    DECIMAL_LITERAL shift and go to state 31
+    STRING_LITERAL  shift and go to state 28
+    DOLLAR          shift and go to state 29
+    RUBLE           shift and go to state 23
+
+    currency                       shift and go to state 22
+    expression                     shift and go to state 42
+
+state 31
+
+    (31) expression -> DECIMAL_LITERAL .
+
+    AND             reduce using rule 31 (expression -> DECIMAL_LITERAL .)
+    OR              reduce using rule 31 (expression -> DECIMAL_LITERAL .)
+    PLUS            reduce using rule 31 (expression -> DECIMAL_LITERAL .)
+    MINUS           reduce using rule 31 (expression -> DECIMAL_LITERAL .)
+    TIMES           reduce using rule 31 (expression -> DECIMAL_LITERAL .)
+    DIVIDE          reduce using rule 31 (expression -> DECIMAL_LITERAL .)
+    EQUALS          reduce using rule 31 (expression -> DECIMAL_LITERAL .)
+    NOT_EQUALS      reduce using rule 31 (expression -> DECIMAL_LITERAL .)
+    LESS_EQUALS     reduce using rule 31 (expression -> DECIMAL_LITERAL .)
+    LESS_THAN       reduce using rule 31 (expression -> DECIMAL_LITERAL .)
+    GREATER_EQUALS  reduce using rule 31 (expression -> DECIMAL_LITERAL .)
+    GREATER_THAN    reduce using rule 31 (expression -> DECIMAL_LITERAL .)
+    IF              reduce using rule 31 (expression -> DECIMAL_LITERAL .)
+    STRING_LITERAL  reduce using rule 31 (expression -> DECIMAL_LITERAL .)
+    RIGHT_BRACE     reduce using rule 31 (expression -> DECIMAL_LITERAL .)
+    RIGHT_BRACKET   reduce using rule 31 (expression -> DECIMAL_LITERAL .)
+
+
+state 32
+
+    (28) expression -> TRUE .
+
+    AND             reduce using rule 28 (expression -> TRUE .)
+    OR              reduce using rule 28 (expression -> TRUE .)
+    PLUS            reduce using rule 28 (expression -> TRUE .)
+    MINUS           reduce using rule 28 (expression -> TRUE .)
+    TIMES           reduce using rule 28 (expression -> TRUE .)
+    DIVIDE          reduce using rule 28 (expression -> TRUE .)
+    EQUALS          reduce using rule 28 (expression -> TRUE .)
+    NOT_EQUALS      reduce using rule 28 (expression -> TRUE .)
+    LESS_EQUALS     reduce using rule 28 (expression -> TRUE .)
+    LESS_THAN       reduce using rule 28 (expression -> TRUE .)
+    GREATER_EQUALS  reduce using rule 28 (expression -> TRUE .)
+    GREATER_THAN    reduce using rule 28 (expression -> TRUE .)
+    IF              reduce using rule 28 (expression -> TRUE .)
+    STRING_LITERAL  reduce using rule 28 (expression -> TRUE .)
+    RIGHT_BRACE     reduce using rule 28 (expression -> TRUE .)
+    RIGHT_BRACKET   reduce using rule 28 (expression -> TRUE .)
+
+
+state 33
+
+    (10) condition -> LEFT_BRACKET expression . RIGHT_BRACKET
+    (15) expression -> expression . AND expression
+    (16) expression -> expression . OR expression
+    (17) expression -> expression . PLUS expression
+    (18) expression -> expression . MINUS expression
+    (19) expression -> expression . TIMES expression
+    (20) expression -> expression . DIVIDE expression
+    (21) expression -> expression . EQUALS expression
+    (22) expression -> expression . NOT_EQUALS expression
+    (23) expression -> expression . LESS_EQUALS expression
+    (24) expression -> expression . LESS_THAN expression
+    (25) expression -> expression . GREATER_EQUALS expression
+    (26) expression -> expression . GREATER_THAN expression
+
+    RIGHT_BRACKET   shift and go to state 43
+    AND             shift and go to state 52
+    OR              shift and go to state 50
+    PLUS            shift and go to state 44
+    MINUS           shift and go to state 48
+    TIMES           shift and go to state 49
+    DIVIDE          shift and go to state 51
+    EQUALS          shift and go to state 46
+    NOT_EQUALS      shift and go to state 45
+    LESS_EQUALS     shift and go to state 54
+    LESS_THAN       shift and go to state 47
+    GREATER_EQUALS  shift and go to state 55
+    GREATER_THAN    shift and go to state 53
+
+
+state 34
+
+    (12) expression -> IDENTIFIER .
+
+    AND             reduce using rule 12 (expression -> IDENTIFIER .)
+    OR              reduce using rule 12 (expression -> IDENTIFIER .)
+    PLUS            reduce using rule 12 (expression -> IDENTIFIER .)
+    MINUS           reduce using rule 12 (expression -> IDENTIFIER .)
+    TIMES           reduce using rule 12 (expression -> IDENTIFIER .)
+    DIVIDE          reduce using rule 12 (expression -> IDENTIFIER .)
+    EQUALS          reduce using rule 12 (expression -> IDENTIFIER .)
+    NOT_EQUALS      reduce using rule 12 (expression -> IDENTIFIER .)
+    LESS_EQUALS     reduce using rule 12 (expression -> IDENTIFIER .)
+    LESS_THAN       reduce using rule 12 (expression -> IDENTIFIER .)
+    GREATER_EQUALS  reduce using rule 12 (expression -> IDENTIFIER .)
+    GREATER_THAN    reduce using rule 12 (expression -> IDENTIFIER .)
+    IF              reduce using rule 12 (expression -> IDENTIFIER .)
+    STRING_LITERAL  reduce using rule 12 (expression -> IDENTIFIER .)
+    RIGHT_BRACE     reduce using rule 12 (expression -> IDENTIFIER .)
+    RIGHT_BRACKET   reduce using rule 12 (expression -> IDENTIFIER .)
+
+
+state 35
+
+    (27) expression -> FALSE .
+
+    AND             reduce using rule 27 (expression -> FALSE .)
+    OR              reduce using rule 27 (expression -> FALSE .)
+    PLUS            reduce using rule 27 (expression -> FALSE .)
+    MINUS           reduce using rule 27 (expression -> FALSE .)
+    TIMES           reduce using rule 27 (expression -> FALSE .)
+    DIVIDE          reduce using rule 27 (expression -> FALSE .)
+    EQUALS          reduce using rule 27 (expression -> FALSE .)
+    NOT_EQUALS      reduce using rule 27 (expression -> FALSE .)
+    LESS_EQUALS     reduce using rule 27 (expression -> FALSE .)
+    LESS_THAN       reduce using rule 27 (expression -> FALSE .)
+    GREATER_EQUALS  reduce using rule 27 (expression -> FALSE .)
+    GREATER_THAN    reduce using rule 27 (expression -> FALSE .)
+    IF              reduce using rule 27 (expression -> FALSE .)
+    STRING_LITERAL  reduce using rule 27 (expression -> FALSE .)
+    RIGHT_BRACE     reduce using rule 27 (expression -> FALSE .)
+    RIGHT_BRACKET   reduce using rule 27 (expression -> FALSE .)
+
+
+state 36
+
+    (7) question -> STRING_LITERAL IDENTIFIER COLON . type
+    (8) question -> STRING_LITERAL IDENTIFIER COLON . type ASSIGN expression
+    (37) type -> . BOOLEAN
+    (38) type -> . DECIMAL
+    (39) type -> . STRING
+    (40) type -> . DATE
+    (41) type -> . MONEY
+    (42) type -> . INTEGER
+
+    BOOLEAN         shift and go to state 62
+    DECIMAL         shift and go to state 57
+    STRING          shift and go to state 58
+    DATE            shift and go to state 56
+    MONEY           shift and go to state 60
+    INTEGER         shift and go to state 61
+
+    type                           shift and go to state 59
+
+state 37
+
+    (45) statement -> IF condition LEFT_BRACE RIGHT_BRACE .
+
+    IF              reduce using rule 45 (statement -> IF condition LEFT_BRACE RIGHT_BRACE .)
+    STRING_LITERAL  reduce using rule 45 (statement -> IF condition LEFT_BRACE RIGHT_BRACE .)
+    RIGHT_BRACE     reduce using rule 45 (statement -> IF condition LEFT_BRACE RIGHT_BRACE .)
+
+
+state 38
+
+    (32) expression -> currency DECIMAL_LITERAL .
+
+    AND             reduce using rule 32 (expression -> currency DECIMAL_LITERAL .)
+    OR              reduce using rule 32 (expression -> currency DECIMAL_LITERAL .)
+    PLUS            reduce using rule 32 (expression -> currency DECIMAL_LITERAL .)
+    MINUS           reduce using rule 32 (expression -> currency DECIMAL_LITERAL .)
+    TIMES           reduce using rule 32 (expression -> currency DECIMAL_LITERAL .)
+    DIVIDE          reduce using rule 32 (expression -> currency DECIMAL_LITERAL .)
+    EQUALS          reduce using rule 32 (expression -> currency DECIMAL_LITERAL .)
+    NOT_EQUALS      reduce using rule 32 (expression -> currency DECIMAL_LITERAL .)
+    LESS_EQUALS     reduce using rule 32 (expression -> currency DECIMAL_LITERAL .)
+    LESS_THAN       reduce using rule 32 (expression -> currency DECIMAL_LITERAL .)
+    GREATER_EQUALS  reduce using rule 32 (expression -> currency DECIMAL_LITERAL .)
+    GREATER_THAN    reduce using rule 32 (expression -> currency DECIMAL_LITERAL .)
+    IF              reduce using rule 32 (expression -> currency DECIMAL_LITERAL .)
+    STRING_LITERAL  reduce using rule 32 (expression -> currency DECIMAL_LITERAL .)
+    RIGHT_BRACE     reduce using rule 32 (expression -> currency DECIMAL_LITERAL .)
+    RIGHT_BRACKET   reduce using rule 32 (expression -> currency DECIMAL_LITERAL .)
+
+
+state 39
+
+    (33) expression -> currency INTEGER_LITERAL .
+
+    AND             reduce using rule 33 (expression -> currency INTEGER_LITERAL .)
+    OR              reduce using rule 33 (expression -> currency INTEGER_LITERAL .)
+    PLUS            reduce using rule 33 (expression -> currency INTEGER_LITERAL .)
+    MINUS           reduce using rule 33 (expression -> currency INTEGER_LITERAL .)
+    TIMES           reduce using rule 33 (expression -> currency INTEGER_LITERAL .)
+    DIVIDE          reduce using rule 33 (expression -> currency INTEGER_LITERAL .)
+    EQUALS          reduce using rule 33 (expression -> currency INTEGER_LITERAL .)
+    NOT_EQUALS      reduce using rule 33 (expression -> currency INTEGER_LITERAL .)
+    LESS_EQUALS     reduce using rule 33 (expression -> currency INTEGER_LITERAL .)
+    LESS_THAN       reduce using rule 33 (expression -> currency INTEGER_LITERAL .)
+    GREATER_EQUALS  reduce using rule 33 (expression -> currency INTEGER_LITERAL .)
+    GREATER_THAN    reduce using rule 33 (expression -> currency INTEGER_LITERAL .)
+    IF              reduce using rule 33 (expression -> currency INTEGER_LITERAL .)
+    STRING_LITERAL  reduce using rule 33 (expression -> currency INTEGER_LITERAL .)
+    RIGHT_BRACE     reduce using rule 33 (expression -> currency INTEGER_LITERAL .)
+    RIGHT_BRACKET   reduce using rule 33 (expression -> currency INTEGER_LITERAL .)
+
+
+state 40
+
+    (14) expression -> MINUS expression .
+    (15) expression -> expression . AND expression
+    (16) expression -> expression . OR expression
+    (17) expression -> expression . PLUS expression
+    (18) expression -> expression . MINUS expression
+    (19) expression -> expression . TIMES expression
+    (20) expression -> expression . DIVIDE expression
+    (21) expression -> expression . EQUALS expression
+    (22) expression -> expression . NOT_EQUALS expression
+    (23) expression -> expression . LESS_EQUALS expression
+    (24) expression -> expression . LESS_THAN expression
+    (25) expression -> expression . GREATER_EQUALS expression
+    (26) expression -> expression . GREATER_THAN expression
+
+    AND             reduce using rule 14 (expression -> MINUS expression .)
+    OR              reduce using rule 14 (expression -> MINUS expression .)
+    PLUS            reduce using rule 14 (expression -> MINUS expression .)
+    MINUS           reduce using rule 14 (expression -> MINUS expression .)
+    EQUALS          reduce using rule 14 (expression -> MINUS expression .)
+    NOT_EQUALS      reduce using rule 14 (expression -> MINUS expression .)
+    LESS_EQUALS     reduce using rule 14 (expression -> MINUS expression .)
+    LESS_THAN       reduce using rule 14 (expression -> MINUS expression .)
+    GREATER_EQUALS  reduce using rule 14 (expression -> MINUS expression .)
+    GREATER_THAN    reduce using rule 14 (expression -> MINUS expression .)
+    IF              reduce using rule 14 (expression -> MINUS expression .)
+    STRING_LITERAL  reduce using rule 14 (expression -> MINUS expression .)
+    RIGHT_BRACE     reduce using rule 14 (expression -> MINUS expression .)
+    RIGHT_BRACKET   reduce using rule 14 (expression -> MINUS expression .)
+    TIMES           shift and go to state 49
+    DIVIDE          shift and go to state 51
+
+  ! TIMES           [ reduce using rule 14 (expression -> MINUS expression .) ]
+  ! DIVIDE          [ reduce using rule 14 (expression -> MINUS expression .) ]
+  ! AND             [ shift and go to state 52 ]
+  ! OR              [ shift and go to state 50 ]
+  ! PLUS            [ shift and go to state 44 ]
+  ! MINUS           [ shift and go to state 48 ]
+  ! EQUALS          [ shift and go to state 46 ]
+  ! NOT_EQUALS      [ shift and go to state 45 ]
+  ! LESS_EQUALS     [ shift and go to state 54 ]
+  ! LESS_THAN       [ shift and go to state 47 ]
+  ! GREATER_EQUALS  [ shift and go to state 55 ]
+  ! GREATER_THAN    [ shift and go to state 53 ]
+
+
+state 41
+
+    (13) expression -> NOT expression .
+    (15) expression -> expression . AND expression
+    (16) expression -> expression . OR expression
+    (17) expression -> expression . PLUS expression
+    (18) expression -> expression . MINUS expression
+    (19) expression -> expression . TIMES expression
+    (20) expression -> expression . DIVIDE expression
+    (21) expression -> expression . EQUALS expression
+    (22) expression -> expression . NOT_EQUALS expression
+    (23) expression -> expression . LESS_EQUALS expression
+    (24) expression -> expression . LESS_THAN expression
+    (25) expression -> expression . GREATER_EQUALS expression
+    (26) expression -> expression . GREATER_THAN expression
+
+    AND             reduce using rule 13 (expression -> NOT expression .)
+    OR              reduce using rule 13 (expression -> NOT expression .)
+    PLUS            reduce using rule 13 (expression -> NOT expression .)
+    MINUS           reduce using rule 13 (expression -> NOT expression .)
+    TIMES           reduce using rule 13 (expression -> NOT expression .)
+    DIVIDE          reduce using rule 13 (expression -> NOT expression .)
+    EQUALS          reduce using rule 13 (expression -> NOT expression .)
+    NOT_EQUALS      reduce using rule 13 (expression -> NOT expression .)
+    LESS_EQUALS     reduce using rule 13 (expression -> NOT expression .)
+    LESS_THAN       reduce using rule 13 (expression -> NOT expression .)
+    GREATER_EQUALS  reduce using rule 13 (expression -> NOT expression .)
+    GREATER_THAN    reduce using rule 13 (expression -> NOT expression .)
+    IF              reduce using rule 13 (expression -> NOT expression .)
+    STRING_LITERAL  reduce using rule 13 (expression -> NOT expression .)
+    RIGHT_BRACE     reduce using rule 13 (expression -> NOT expression .)
+    RIGHT_BRACKET   reduce using rule 13 (expression -> NOT expression .)
+
+  ! AND             [ shift and go to state 52 ]
+  ! OR              [ shift and go to state 50 ]
+  ! PLUS            [ shift and go to state 44 ]
+  ! MINUS           [ shift and go to state 48 ]
+  ! TIMES           [ shift and go to state 49 ]
+  ! DIVIDE          [ shift and go to state 51 ]
+  ! EQUALS          [ shift and go to state 46 ]
+  ! NOT_EQUALS      [ shift and go to state 45 ]
+  ! LESS_EQUALS     [ shift and go to state 54 ]
+  ! LESS_THAN       [ shift and go to state 47 ]
+  ! GREATER_EQUALS  [ shift and go to state 55 ]
+  ! GREATER_THAN    [ shift and go to state 53 ]
+
+
+state 42
+
+    (11) expression -> LEFT_BRACKET expression . RIGHT_BRACKET
+    (15) expression -> expression . AND expression
+    (16) expression -> expression . OR expression
+    (17) expression -> expression . PLUS expression
+    (18) expression -> expression . MINUS expression
+    (19) expression -> expression . TIMES expression
+    (20) expression -> expression . DIVIDE expression
+    (21) expression -> expression . EQUALS expression
+    (22) expression -> expression . NOT_EQUALS expression
+    (23) expression -> expression . LESS_EQUALS expression
+    (24) expression -> expression . LESS_THAN expression
+    (25) expression -> expression . GREATER_EQUALS expression
+    (26) expression -> expression . GREATER_THAN expression
+
+    RIGHT_BRACKET   shift and go to state 63
+    AND             shift and go to state 52
+    OR              shift and go to state 50
+    PLUS            shift and go to state 44
+    MINUS           shift and go to state 48
+    TIMES           shift and go to state 49
+    DIVIDE          shift and go to state 51
+    EQUALS          shift and go to state 46
+    NOT_EQUALS      shift and go to state 45
+    LESS_EQUALS     shift and go to state 54
+    LESS_THAN       shift and go to state 47
+    GREATER_EQUALS  shift and go to state 55
+    GREATER_THAN    shift and go to state 53
+
+
+state 43
+
+    (10) condition -> LEFT_BRACKET expression RIGHT_BRACKET .
+
+    LEFT_BRACE      reduce using rule 10 (condition -> LEFT_BRACKET expression RIGHT_BRACKET .)
+
+
+state 44
+
+    (17) expression -> expression PLUS . expression
+    (11) expression -> . LEFT_BRACKET expression RIGHT_BRACKET
+    (12) expression -> . IDENTIFIER
+    (13) expression -> . NOT expression
+    (14) expression -> . MINUS expression
+    (15) expression -> . expression AND expression
+    (16) expression -> . expression OR expression
+    (17) expression -> . expression PLUS expression
+    (18) expression -> . expression MINUS expression
+    (19) expression -> . expression TIMES expression
+    (20) expression -> . expression DIVIDE expression
+    (21) expression -> . expression EQUALS expression
+    (22) expression -> . expression NOT_EQUALS expression
+    (23) expression -> . expression LESS_EQUALS expression
+    (24) expression -> . expression LESS_THAN expression
+    (25) expression -> . expression GREATER_EQUALS expression
+    (26) expression -> . expression GREATER_THAN expression
+    (27) expression -> . FALSE
+    (28) expression -> . TRUE
+    (29) expression -> . DATE_LITERAL
+    (30) expression -> . INTEGER_LITERAL
+    (31) expression -> . DECIMAL_LITERAL
+    (32) expression -> . currency DECIMAL_LITERAL
+    (33) expression -> . currency INTEGER_LITERAL
+    (34) expression -> . STRING_LITERAL
+    (35) currency -> . DOLLAR
+    (36) currency -> . RUBLE
+
+    LEFT_BRACKET    shift and go to state 30
+    IDENTIFIER      shift and go to state 34
+    NOT             shift and go to state 27
+    MINUS           shift and go to state 25
+    FALSE           shift and go to state 35
+    TRUE            shift and go to state 32
+    DATE_LITERAL    shift and go to state 24
+    INTEGER_LITERAL shift and go to state 26
+    DECIMAL_LITERAL shift and go to state 31
+    STRING_LITERAL  shift and go to state 28
+    DOLLAR          shift and go to state 29
+    RUBLE           shift and go to state 23
+
+    currency                       shift and go to state 22
+    expression                     shift and go to state 64
+
+state 45
+
+    (22) expression -> expression NOT_EQUALS . expression
+    (11) expression -> . LEFT_BRACKET expression RIGHT_BRACKET
+    (12) expression -> . IDENTIFIER
+    (13) expression -> . NOT expression
+    (14) expression -> . MINUS expression
+    (15) expression -> . expression AND expression
+    (16) expression -> . expression OR expression
+    (17) expression -> . expression PLUS expression
+    (18) expression -> . expression MINUS expression
+    (19) expression -> . expression TIMES expression
+    (20) expression -> . expression DIVIDE expression
+    (21) expression -> . expression EQUALS expression
+    (22) expression -> . expression NOT_EQUALS expression
+    (23) expression -> . expression LESS_EQUALS expression
+    (24) expression -> . expression LESS_THAN expression
+    (25) expression -> . expression GREATER_EQUALS expression
+    (26) expression -> . expression GREATER_THAN expression
+    (27) expression -> . FALSE
+    (28) expression -> . TRUE
+    (29) expression -> . DATE_LITERAL
+    (30) expression -> . INTEGER_LITERAL
+    (31) expression -> . DECIMAL_LITERAL
+    (32) expression -> . currency DECIMAL_LITERAL
+    (33) expression -> . currency INTEGER_LITERAL
+    (34) expression -> . STRING_LITERAL
+    (35) currency -> . DOLLAR
+    (36) currency -> . RUBLE
+
+    LEFT_BRACKET    shift and go to state 30
+    IDENTIFIER      shift and go to state 34
+    NOT             shift and go to state 27
+    MINUS           shift and go to state 25
+    FALSE           shift and go to state 35
+    TRUE            shift and go to state 32
+    DATE_LITERAL    shift and go to state 24
+    INTEGER_LITERAL shift and go to state 26
+    DECIMAL_LITERAL shift and go to state 31
+    STRING_LITERAL  shift and go to state 28
+    DOLLAR          shift and go to state 29
+    RUBLE           shift and go to state 23
+
+    currency                       shift and go to state 22
+    expression                     shift and go to state 65
+
+state 46
+
+    (21) expression -> expression EQUALS . expression
+    (11) expression -> . LEFT_BRACKET expression RIGHT_BRACKET
+    (12) expression -> . IDENTIFIER
+    (13) expression -> . NOT expression
+    (14) expression -> . MINUS expression
+    (15) expression -> . expression AND expression
+    (16) expression -> . expression OR expression
+    (17) expression -> . expression PLUS expression
+    (18) expression -> . expression MINUS expression
+    (19) expression -> . expression TIMES expression
+    (20) expression -> . expression DIVIDE expression
+    (21) expression -> . expression EQUALS expression
+    (22) expression -> . expression NOT_EQUALS expression
+    (23) expression -> . expression LESS_EQUALS expression
+    (24) expression -> . expression LESS_THAN expression
+    (25) expression -> . expression GREATER_EQUALS expression
+    (26) expression -> . expression GREATER_THAN expression
+    (27) expression -> . FALSE
+    (28) expression -> . TRUE
+    (29) expression -> . DATE_LITERAL
+    (30) expression -> . INTEGER_LITERAL
+    (31) expression -> . DECIMAL_LITERAL
+    (32) expression -> . currency DECIMAL_LITERAL
+    (33) expression -> . currency INTEGER_LITERAL
+    (34) expression -> . STRING_LITERAL
+    (35) currency -> . DOLLAR
+    (36) currency -> . RUBLE
+
+    LEFT_BRACKET    shift and go to state 30
+    IDENTIFIER      shift and go to state 34
+    NOT             shift and go to state 27
+    MINUS           shift and go to state 25
+    FALSE           shift and go to state 35
+    TRUE            shift and go to state 32
+    DATE_LITERAL    shift and go to state 24
+    INTEGER_LITERAL shift and go to state 26
+    DECIMAL_LITERAL shift and go to state 31
+    STRING_LITERAL  shift and go to state 28
+    DOLLAR          shift and go to state 29
+    RUBLE           shift and go to state 23
+
+    currency                       shift and go to state 22
+    expression                     shift and go to state 66
+
+state 47
+
+    (24) expression -> expression LESS_THAN . expression
+    (11) expression -> . LEFT_BRACKET expression RIGHT_BRACKET
+    (12) expression -> . IDENTIFIER
+    (13) expression -> . NOT expression
+    (14) expression -> . MINUS expression
+    (15) expression -> . expression AND expression
+    (16) expression -> . expression OR expression
+    (17) expression -> . expression PLUS expression
+    (18) expression -> . expression MINUS expression
+    (19) expression -> . expression TIMES expression
+    (20) expression -> . expression DIVIDE expression
+    (21) expression -> . expression EQUALS expression
+    (22) expression -> . expression NOT_EQUALS expression
+    (23) expression -> . expression LESS_EQUALS expression
+    (24) expression -> . expression LESS_THAN expression
+    (25) expression -> . expression GREATER_EQUALS expression
+    (26) expression -> . expression GREATER_THAN expression
+    (27) expression -> . FALSE
+    (28) expression -> . TRUE
+    (29) expression -> . DATE_LITERAL
+    (30) expression -> . INTEGER_LITERAL
+    (31) expression -> . DECIMAL_LITERAL
+    (32) expression -> . currency DECIMAL_LITERAL
+    (33) expression -> . currency INTEGER_LITERAL
+    (34) expression -> . STRING_LITERAL
+    (35) currency -> . DOLLAR
+    (36) currency -> . RUBLE
+
+    LEFT_BRACKET    shift and go to state 30
+    IDENTIFIER      shift and go to state 34
+    NOT             shift and go to state 27
+    MINUS           shift and go to state 25
+    FALSE           shift and go to state 35
+    TRUE            shift and go to state 32
+    DATE_LITERAL    shift and go to state 24
+    INTEGER_LITERAL shift and go to state 26
+    DECIMAL_LITERAL shift and go to state 31
+    STRING_LITERAL  shift and go to state 28
+    DOLLAR          shift and go to state 29
+    RUBLE           shift and go to state 23
+
+    currency                       shift and go to state 22
+    expression                     shift and go to state 67
+
+state 48
+
+    (18) expression -> expression MINUS . expression
+    (11) expression -> . LEFT_BRACKET expression RIGHT_BRACKET
+    (12) expression -> . IDENTIFIER
+    (13) expression -> . NOT expression
+    (14) expression -> . MINUS expression
+    (15) expression -> . expression AND expression
+    (16) expression -> . expression OR expression
+    (17) expression -> . expression PLUS expression
+    (18) expression -> . expression MINUS expression
+    (19) expression -> . expression TIMES expression
+    (20) expression -> . expression DIVIDE expression
+    (21) expression -> . expression EQUALS expression
+    (22) expression -> . expression NOT_EQUALS expression
+    (23) expression -> . expression LESS_EQUALS expression
+    (24) expression -> . expression LESS_THAN expression
+    (25) expression -> . expression GREATER_EQUALS expression
+    (26) expression -> . expression GREATER_THAN expression
+    (27) expression -> . FALSE
+    (28) expression -> . TRUE
+    (29) expression -> . DATE_LITERAL
+    (30) expression -> . INTEGER_LITERAL
+    (31) expression -> . DECIMAL_LITERAL
+    (32) expression -> . currency DECIMAL_LITERAL
+    (33) expression -> . currency INTEGER_LITERAL
+    (34) expression -> . STRING_LITERAL
+    (35) currency -> . DOLLAR
+    (36) currency -> . RUBLE
+
+    LEFT_BRACKET    shift and go to state 30
+    IDENTIFIER      shift and go to state 34
+    NOT             shift and go to state 27
+    MINUS           shift and go to state 25
+    FALSE           shift and go to state 35
+    TRUE            shift and go to state 32
+    DATE_LITERAL    shift and go to state 24
+    INTEGER_LITERAL shift and go to state 26
+    DECIMAL_LITERAL shift and go to state 31
+    STRING_LITERAL  shift and go to state 28
+    DOLLAR          shift and go to state 29
+    RUBLE           shift and go to state 23
+
+    currency                       shift and go to state 22
+    expression                     shift and go to state 68
+
+state 49
+
+    (19) expression -> expression TIMES . expression
+    (11) expression -> . LEFT_BRACKET expression RIGHT_BRACKET
+    (12) expression -> . IDENTIFIER
+    (13) expression -> . NOT expression
+    (14) expression -> . MINUS expression
+    (15) expression -> . expression AND expression
+    (16) expression -> . expression OR expression
+    (17) expression -> . expression PLUS expression
+    (18) expression -> . expression MINUS expression
+    (19) expression -> . expression TIMES expression
+    (20) expression -> . expression DIVIDE expression
+    (21) expression -> . expression EQUALS expression
+    (22) expression -> . expression NOT_EQUALS expression
+    (23) expression -> . expression LESS_EQUALS expression
+    (24) expression -> . expression LESS_THAN expression
+    (25) expression -> . expression GREATER_EQUALS expression
+    (26) expression -> . expression GREATER_THAN expression
+    (27) expression -> . FALSE
+    (28) expression -> . TRUE
+    (29) expression -> . DATE_LITERAL
+    (30) expression -> . INTEGER_LITERAL
+    (31) expression -> . DECIMAL_LITERAL
+    (32) expression -> . currency DECIMAL_LITERAL
+    (33) expression -> . currency INTEGER_LITERAL
+    (34) expression -> . STRING_LITERAL
+    (35) currency -> . DOLLAR
+    (36) currency -> . RUBLE
+
+    LEFT_BRACKET    shift and go to state 30
+    IDENTIFIER      shift and go to state 34
+    NOT             shift and go to state 27
+    MINUS           shift and go to state 25
+    FALSE           shift and go to state 35
+    TRUE            shift and go to state 32
+    DATE_LITERAL    shift and go to state 24
+    INTEGER_LITERAL shift and go to state 26
+    DECIMAL_LITERAL shift and go to state 31
+    STRING_LITERAL  shift and go to state 28
+    DOLLAR          shift and go to state 29
+    RUBLE           shift and go to state 23
+
+    currency                       shift and go to state 22
+    expression                     shift and go to state 69
+
+state 50
+
+    (16) expression -> expression OR . expression
+    (11) expression -> . LEFT_BRACKET expression RIGHT_BRACKET
+    (12) expression -> . IDENTIFIER
+    (13) expression -> . NOT expression
+    (14) expression -> . MINUS expression
+    (15) expression -> . expression AND expression
+    (16) expression -> . expression OR expression
+    (17) expression -> . expression PLUS expression
+    (18) expression -> . expression MINUS expression
+    (19) expression -> . expression TIMES expression
+    (20) expression -> . expression DIVIDE expression
+    (21) expression -> . expression EQUALS expression
+    (22) expression -> . expression NOT_EQUALS expression
+    (23) expression -> . expression LESS_EQUALS expression
+    (24) expression -> . expression LESS_THAN expression
+    (25) expression -> . expression GREATER_EQUALS expression
+    (26) expression -> . expression GREATER_THAN expression
+    (27) expression -> . FALSE
+    (28) expression -> . TRUE
+    (29) expression -> . DATE_LITERAL
+    (30) expression -> . INTEGER_LITERAL
+    (31) expression -> . DECIMAL_LITERAL
+    (32) expression -> . currency DECIMAL_LITERAL
+    (33) expression -> . currency INTEGER_LITERAL
+    (34) expression -> . STRING_LITERAL
+    (35) currency -> . DOLLAR
+    (36) currency -> . RUBLE
+
+    LEFT_BRACKET    shift and go to state 30
+    IDENTIFIER      shift and go to state 34
+    NOT             shift and go to state 27
+    MINUS           shift and go to state 25
+    FALSE           shift and go to state 35
+    TRUE            shift and go to state 32
+    DATE_LITERAL    shift and go to state 24
+    INTEGER_LITERAL shift and go to state 26
+    DECIMAL_LITERAL shift and go to state 31
+    STRING_LITERAL  shift and go to state 28
+    DOLLAR          shift and go to state 29
+    RUBLE           shift and go to state 23
+
+    currency                       shift and go to state 22
+    expression                     shift and go to state 70
+
+state 51
+
+    (20) expression -> expression DIVIDE . expression
+    (11) expression -> . LEFT_BRACKET expression RIGHT_BRACKET
+    (12) expression -> . IDENTIFIER
+    (13) expression -> . NOT expression
+    (14) expression -> . MINUS expression
+    (15) expression -> . expression AND expression
+    (16) expression -> . expression OR expression
+    (17) expression -> . expression PLUS expression
+    (18) expression -> . expression MINUS expression
+    (19) expression -> . expression TIMES expression
+    (20) expression -> . expression DIVIDE expression
+    (21) expression -> . expression EQUALS expression
+    (22) expression -> . expression NOT_EQUALS expression
+    (23) expression -> . expression LESS_EQUALS expression
+    (24) expression -> . expression LESS_THAN expression
+    (25) expression -> . expression GREATER_EQUALS expression
+    (26) expression -> . expression GREATER_THAN expression
+    (27) expression -> . FALSE
+    (28) expression -> . TRUE
+    (29) expression -> . DATE_LITERAL
+    (30) expression -> . INTEGER_LITERAL
+    (31) expression -> . DECIMAL_LITERAL
+    (32) expression -> . currency DECIMAL_LITERAL
+    (33) expression -> . currency INTEGER_LITERAL
+    (34) expression -> . STRING_LITERAL
+    (35) currency -> . DOLLAR
+    (36) currency -> . RUBLE
+
+    LEFT_BRACKET    shift and go to state 30
+    IDENTIFIER      shift and go to state 34
+    NOT             shift and go to state 27
+    MINUS           shift and go to state 25
+    FALSE           shift and go to state 35
+    TRUE            shift and go to state 32
+    DATE_LITERAL    shift and go to state 24
+    INTEGER_LITERAL shift and go to state 26
+    DECIMAL_LITERAL shift and go to state 31
+    STRING_LITERAL  shift and go to state 28
+    DOLLAR          shift and go to state 29
+    RUBLE           shift and go to state 23
+
+    currency                       shift and go to state 22
+    expression                     shift and go to state 71
+
+state 52
+
+    (15) expression -> expression AND . expression
+    (11) expression -> . LEFT_BRACKET expression RIGHT_BRACKET
+    (12) expression -> . IDENTIFIER
+    (13) expression -> . NOT expression
+    (14) expression -> . MINUS expression
+    (15) expression -> . expression AND expression
+    (16) expression -> . expression OR expression
+    (17) expression -> . expression PLUS expression
+    (18) expression -> . expression MINUS expression
+    (19) expression -> . expression TIMES expression
+    (20) expression -> . expression DIVIDE expression
+    (21) expression -> . expression EQUALS expression
+    (22) expression -> . expression NOT_EQUALS expression
+    (23) expression -> . expression LESS_EQUALS expression
+    (24) expression -> . expression LESS_THAN expression
+    (25) expression -> . expression GREATER_EQUALS expression
+    (26) expression -> . expression GREATER_THAN expression
+    (27) expression -> . FALSE
+    (28) expression -> . TRUE
+    (29) expression -> . DATE_LITERAL
+    (30) expression -> . INTEGER_LITERAL
+    (31) expression -> . DECIMAL_LITERAL
+    (32) expression -> . currency DECIMAL_LITERAL
+    (33) expression -> . currency INTEGER_LITERAL
+    (34) expression -> . STRING_LITERAL
+    (35) currency -> . DOLLAR
+    (36) currency -> . RUBLE
+
+    LEFT_BRACKET    shift and go to state 30
+    IDENTIFIER      shift and go to state 34
+    NOT             shift and go to state 27
+    MINUS           shift and go to state 25
+    FALSE           shift and go to state 35
+    TRUE            shift and go to state 32
+    DATE_LITERAL    shift and go to state 24
+    INTEGER_LITERAL shift and go to state 26
+    DECIMAL_LITERAL shift and go to state 31
+    STRING_LITERAL  shift and go to state 28
+    DOLLAR          shift and go to state 29
+    RUBLE           shift and go to state 23
+
+    currency                       shift and go to state 22
+    expression                     shift and go to state 72
+
+state 53
+
+    (26) expression -> expression GREATER_THAN . expression
+    (11) expression -> . LEFT_BRACKET expression RIGHT_BRACKET
+    (12) expression -> . IDENTIFIER
+    (13) expression -> . NOT expression
+    (14) expression -> . MINUS expression
+    (15) expression -> . expression AND expression
+    (16) expression -> . expression OR expression
+    (17) expression -> . expression PLUS expression
+    (18) expression -> . expression MINUS expression
+    (19) expression -> . expression TIMES expression
+    (20) expression -> . expression DIVIDE expression
+    (21) expression -> . expression EQUALS expression
+    (22) expression -> . expression NOT_EQUALS expression
+    (23) expression -> . expression LESS_EQUALS expression
+    (24) expression -> . expression LESS_THAN expression
+    (25) expression -> . expression GREATER_EQUALS expression
+    (26) expression -> . expression GREATER_THAN expression
+    (27) expression -> . FALSE
+    (28) expression -> . TRUE
+    (29) expression -> . DATE_LITERAL
+    (30) expression -> . INTEGER_LITERAL
+    (31) expression -> . DECIMAL_LITERAL
+    (32) expression -> . currency DECIMAL_LITERAL
+    (33) expression -> . currency INTEGER_LITERAL
+    (34) expression -> . STRING_LITERAL
+    (35) currency -> . DOLLAR
+    (36) currency -> . RUBLE
+
+    LEFT_BRACKET    shift and go to state 30
+    IDENTIFIER      shift and go to state 34
+    NOT             shift and go to state 27
+    MINUS           shift and go to state 25
+    FALSE           shift and go to state 35
+    TRUE            shift and go to state 32
+    DATE_LITERAL    shift and go to state 24
+    INTEGER_LITERAL shift and go to state 26
+    DECIMAL_LITERAL shift and go to state 31
+    STRING_LITERAL  shift and go to state 28
+    DOLLAR          shift and go to state 29
+    RUBLE           shift and go to state 23
+
+    currency                       shift and go to state 22
+    expression                     shift and go to state 73
+
+state 54
+
+    (23) expression -> expression LESS_EQUALS . expression
+    (11) expression -> . LEFT_BRACKET expression RIGHT_BRACKET
+    (12) expression -> . IDENTIFIER
+    (13) expression -> . NOT expression
+    (14) expression -> . MINUS expression
+    (15) expression -> . expression AND expression
+    (16) expression -> . expression OR expression
+    (17) expression -> . expression PLUS expression
+    (18) expression -> . expression MINUS expression
+    (19) expression -> . expression TIMES expression
+    (20) expression -> . expression DIVIDE expression
+    (21) expression -> . expression EQUALS expression
+    (22) expression -> . expression NOT_EQUALS expression
+    (23) expression -> . expression LESS_EQUALS expression
+    (24) expression -> . expression LESS_THAN expression
+    (25) expression -> . expression GREATER_EQUALS expression
+    (26) expression -> . expression GREATER_THAN expression
+    (27) expression -> . FALSE
+    (28) expression -> . TRUE
+    (29) expression -> . DATE_LITERAL
+    (30) expression -> . INTEGER_LITERAL
+    (31) expression -> . DECIMAL_LITERAL
+    (32) expression -> . currency DECIMAL_LITERAL
+    (33) expression -> . currency INTEGER_LITERAL
+    (34) expression -> . STRING_LITERAL
+    (35) currency -> . DOLLAR
+    (36) currency -> . RUBLE
+
+    LEFT_BRACKET    shift and go to state 30
+    IDENTIFIER      shift and go to state 34
+    NOT             shift and go to state 27
+    MINUS           shift and go to state 25
+    FALSE           shift and go to state 35
+    TRUE            shift and go to state 32
+    DATE_LITERAL    shift and go to state 24
+    INTEGER_LITERAL shift and go to state 26
+    DECIMAL_LITERAL shift and go to state 31
+    STRING_LITERAL  shift and go to state 28
+    DOLLAR          shift and go to state 29
+    RUBLE           shift and go to state 23
+
+    currency                       shift and go to state 22
+    expression                     shift and go to state 74
+
+state 55
+
+    (25) expression -> expression GREATER_EQUALS . expression
+    (11) expression -> . LEFT_BRACKET expression RIGHT_BRACKET
+    (12) expression -> . IDENTIFIER
+    (13) expression -> . NOT expression
+    (14) expression -> . MINUS expression
+    (15) expression -> . expression AND expression
+    (16) expression -> . expression OR expression
+    (17) expression -> . expression PLUS expression
+    (18) expression -> . expression MINUS expression
+    (19) expression -> . expression TIMES expression
+    (20) expression -> . expression DIVIDE expression
+    (21) expression -> . expression EQUALS expression
+    (22) expression -> . expression NOT_EQUALS expression
+    (23) expression -> . expression LESS_EQUALS expression
+    (24) expression -> . expression LESS_THAN expression
+    (25) expression -> . expression GREATER_EQUALS expression
+    (26) expression -> . expression GREATER_THAN expression
+    (27) expression -> . FALSE
+    (28) expression -> . TRUE
+    (29) expression -> . DATE_LITERAL
+    (30) expression -> . INTEGER_LITERAL
+    (31) expression -> . DECIMAL_LITERAL
+    (32) expression -> . currency DECIMAL_LITERAL
+    (33) expression -> . currency INTEGER_LITERAL
+    (34) expression -> . STRING_LITERAL
+    (35) currency -> . DOLLAR
+    (36) currency -> . RUBLE
+
+    LEFT_BRACKET    shift and go to state 30
+    IDENTIFIER      shift and go to state 34
+    NOT             shift and go to state 27
+    MINUS           shift and go to state 25
+    FALSE           shift and go to state 35
+    TRUE            shift and go to state 32
+    DATE_LITERAL    shift and go to state 24
+    INTEGER_LITERAL shift and go to state 26
+    DECIMAL_LITERAL shift and go to state 31
+    STRING_LITERAL  shift and go to state 28
+    DOLLAR          shift and go to state 29
+    RUBLE           shift and go to state 23
+
+    currency                       shift and go to state 22
+    expression                     shift and go to state 75
+
+state 56
+
+    (40) type -> DATE .
+
+    ASSIGN          reduce using rule 40 (type -> DATE .)
+    IF              reduce using rule 40 (type -> DATE .)
+    STRING_LITERAL  reduce using rule 40 (type -> DATE .)
+    RIGHT_BRACE     reduce using rule 40 (type -> DATE .)
+
+
+state 57
+
+    (38) type -> DECIMAL .
+
+    ASSIGN          reduce using rule 38 (type -> DECIMAL .)
+    IF              reduce using rule 38 (type -> DECIMAL .)
+    STRING_LITERAL  reduce using rule 38 (type -> DECIMAL .)
+    RIGHT_BRACE     reduce using rule 38 (type -> DECIMAL .)
+
+
+state 58
+
+    (39) type -> STRING .
+
+    ASSIGN          reduce using rule 39 (type -> STRING .)
+    IF              reduce using rule 39 (type -> STRING .)
+    STRING_LITERAL  reduce using rule 39 (type -> STRING .)
+    RIGHT_BRACE     reduce using rule 39 (type -> STRING .)
+
+
+state 59
+
+    (7) question -> STRING_LITERAL IDENTIFIER COLON type .
+    (8) question -> STRING_LITERAL IDENTIFIER COLON type . ASSIGN expression
+
+    IF              reduce using rule 7 (question -> STRING_LITERAL IDENTIFIER COLON type .)
+    STRING_LITERAL  reduce using rule 7 (question -> STRING_LITERAL IDENTIFIER COLON type .)
+    RIGHT_BRACE     reduce using rule 7 (question -> STRING_LITERAL IDENTIFIER COLON type .)
+    ASSIGN          shift and go to state 76
+
+
+state 60
+
+    (41) type -> MONEY .
+
+    ASSIGN          reduce using rule 41 (type -> MONEY .)
+    IF              reduce using rule 41 (type -> MONEY .)
+    STRING_LITERAL  reduce using rule 41 (type -> MONEY .)
+    RIGHT_BRACE     reduce using rule 41 (type -> MONEY .)
+
+
+state 61
+
+    (42) type -> INTEGER .
+
+    ASSIGN          reduce using rule 42 (type -> INTEGER .)
+    IF              reduce using rule 42 (type -> INTEGER .)
+    STRING_LITERAL  reduce using rule 42 (type -> INTEGER .)
+    RIGHT_BRACE     reduce using rule 42 (type -> INTEGER .)
+
+
+state 62
+
+    (37) type -> BOOLEAN .
+
+    ASSIGN          reduce using rule 37 (type -> BOOLEAN .)
+    IF              reduce using rule 37 (type -> BOOLEAN .)
+    STRING_LITERAL  reduce using rule 37 (type -> BOOLEAN .)
+    RIGHT_BRACE     reduce using rule 37 (type -> BOOLEAN .)
+
+
+state 63
+
+    (11) expression -> LEFT_BRACKET expression RIGHT_BRACKET .
+
+    AND             reduce using rule 11 (expression -> LEFT_BRACKET expression RIGHT_BRACKET .)
+    OR              reduce using rule 11 (expression -> LEFT_BRACKET expression RIGHT_BRACKET .)
+    PLUS            reduce using rule 11 (expression -> LEFT_BRACKET expression RIGHT_BRACKET .)
+    MINUS           reduce using rule 11 (expression -> LEFT_BRACKET expression RIGHT_BRACKET .)
+    TIMES           reduce using rule 11 (expression -> LEFT_BRACKET expression RIGHT_BRACKET .)
+    DIVIDE          reduce using rule 11 (expression -> LEFT_BRACKET expression RIGHT_BRACKET .)
+    EQUALS          reduce using rule 11 (expression -> LEFT_BRACKET expression RIGHT_BRACKET .)
+    NOT_EQUALS      reduce using rule 11 (expression -> LEFT_BRACKET expression RIGHT_BRACKET .)
+    LESS_EQUALS     reduce using rule 11 (expression -> LEFT_BRACKET expression RIGHT_BRACKET .)
+    LESS_THAN       reduce using rule 11 (expression -> LEFT_BRACKET expression RIGHT_BRACKET .)
+    GREATER_EQUALS  reduce using rule 11 (expression -> LEFT_BRACKET expression RIGHT_BRACKET .)
+    GREATER_THAN    reduce using rule 11 (expression -> LEFT_BRACKET expression RIGHT_BRACKET .)
+    IF              reduce using rule 11 (expression -> LEFT_BRACKET expression RIGHT_BRACKET .)
+    STRING_LITERAL  reduce using rule 11 (expression -> LEFT_BRACKET expression RIGHT_BRACKET .)
+    RIGHT_BRACE     reduce using rule 11 (expression -> LEFT_BRACKET expression RIGHT_BRACKET .)
+    RIGHT_BRACKET   reduce using rule 11 (expression -> LEFT_BRACKET expression RIGHT_BRACKET .)
+
+
+state 64
+
+    (17) expression -> expression PLUS expression .
+    (15) expression -> expression . AND expression
+    (16) expression -> expression . OR expression
+    (17) expression -> expression . PLUS expression
+    (18) expression -> expression . MINUS expression
+    (19) expression -> expression . TIMES expression
+    (20) expression -> expression . DIVIDE expression
+    (21) expression -> expression . EQUALS expression
+    (22) expression -> expression . NOT_EQUALS expression
+    (23) expression -> expression . LESS_EQUALS expression
+    (24) expression -> expression . LESS_THAN expression
+    (25) expression -> expression . GREATER_EQUALS expression
+    (26) expression -> expression . GREATER_THAN expression
+
+    AND             reduce using rule 17 (expression -> expression PLUS expression .)
+    OR              reduce using rule 17 (expression -> expression PLUS expression .)
+    PLUS            reduce using rule 17 (expression -> expression PLUS expression .)
+    MINUS           reduce using rule 17 (expression -> expression PLUS expression .)
+    EQUALS          reduce using rule 17 (expression -> expression PLUS expression .)
+    NOT_EQUALS      reduce using rule 17 (expression -> expression PLUS expression .)
+    LESS_EQUALS     reduce using rule 17 (expression -> expression PLUS expression .)
+    LESS_THAN       reduce using rule 17 (expression -> expression PLUS expression .)
+    GREATER_EQUALS  reduce using rule 17 (expression -> expression PLUS expression .)
+    GREATER_THAN    reduce using rule 17 (expression -> expression PLUS expression .)
+    IF              reduce using rule 17 (expression -> expression PLUS expression .)
+    STRING_LITERAL  reduce using rule 17 (expression -> expression PLUS expression .)
+    RIGHT_BRACE     reduce using rule 17 (expression -> expression PLUS expression .)
+    RIGHT_BRACKET   reduce using rule 17 (expression -> expression PLUS expression .)
+    TIMES           shift and go to state 49
+    DIVIDE          shift and go to state 51
+
+  ! TIMES           [ reduce using rule 17 (expression -> expression PLUS expression .) ]
+  ! DIVIDE          [ reduce using rule 17 (expression -> expression PLUS expression .) ]
+  ! AND             [ shift and go to state 52 ]
+  ! OR              [ shift and go to state 50 ]
+  ! PLUS            [ shift and go to state 44 ]
+  ! MINUS           [ shift and go to state 48 ]
+  ! EQUALS          [ shift and go to state 46 ]
+  ! NOT_EQUALS      [ shift and go to state 45 ]
+  ! LESS_EQUALS     [ shift and go to state 54 ]
+  ! LESS_THAN       [ shift and go to state 47 ]
+  ! GREATER_EQUALS  [ shift and go to state 55 ]
+  ! GREATER_THAN    [ shift and go to state 53 ]
+
+
+state 65
+
+    (22) expression -> expression NOT_EQUALS expression .
+    (15) expression -> expression . AND expression
+    (16) expression -> expression . OR expression
+    (17) expression -> expression . PLUS expression
+    (18) expression -> expression . MINUS expression
+    (19) expression -> expression . TIMES expression
+    (20) expression -> expression . DIVIDE expression
+    (21) expression -> expression . EQUALS expression
+    (22) expression -> expression . NOT_EQUALS expression
+    (23) expression -> expression . LESS_EQUALS expression
+    (24) expression -> expression . LESS_THAN expression
+    (25) expression -> expression . GREATER_EQUALS expression
+    (26) expression -> expression . GREATER_THAN expression
+
+    AND             reduce using rule 22 (expression -> expression NOT_EQUALS expression .)
+    OR              reduce using rule 22 (expression -> expression NOT_EQUALS expression .)
+    EQUALS          reduce using rule 22 (expression -> expression NOT_EQUALS expression .)
+    NOT_EQUALS      reduce using rule 22 (expression -> expression NOT_EQUALS expression .)
+    IF              reduce using rule 22 (expression -> expression NOT_EQUALS expression .)
+    STRING_LITERAL  reduce using rule 22 (expression -> expression NOT_EQUALS expression .)
+    RIGHT_BRACE     reduce using rule 22 (expression -> expression NOT_EQUALS expression .)
+    RIGHT_BRACKET   reduce using rule 22 (expression -> expression NOT_EQUALS expression .)
+    PLUS            shift and go to state 44
+    MINUS           shift and go to state 48
+    TIMES           shift and go to state 49
+    DIVIDE          shift and go to state 51
+    LESS_EQUALS     shift and go to state 54
+    LESS_THAN       shift and go to state 47
+    GREATER_EQUALS  shift and go to state 55
+    GREATER_THAN    shift and go to state 53
+
+  ! PLUS            [ reduce using rule 22 (expression -> expression NOT_EQUALS expression .) ]
+  ! MINUS           [ reduce using rule 22 (expression -> expression NOT_EQUALS expression .) ]
+  ! TIMES           [ reduce using rule 22 (expression -> expression NOT_EQUALS expression .) ]
+  ! DIVIDE          [ reduce using rule 22 (expression -> expression NOT_EQUALS expression .) ]
+  ! LESS_EQUALS     [ reduce using rule 22 (expression -> expression NOT_EQUALS expression .) ]
+  ! LESS_THAN       [ reduce using rule 22 (expression -> expression NOT_EQUALS expression .) ]
+  ! GREATER_EQUALS  [ reduce using rule 22 (expression -> expression NOT_EQUALS expression .) ]
+  ! GREATER_THAN    [ reduce using rule 22 (expression -> expression NOT_EQUALS expression .) ]
+  ! AND             [ shift and go to state 52 ]
+  ! OR              [ shift and go to state 50 ]
+  ! EQUALS          [ shift and go to state 46 ]
+  ! NOT_EQUALS      [ shift and go to state 45 ]
+
+
+state 66
+
+    (21) expression -> expression EQUALS expression .
+    (15) expression -> expression . AND expression
+    (16) expression -> expression . OR expression
+    (17) expression -> expression . PLUS expression
+    (18) expression -> expression . MINUS expression
+    (19) expression -> expression . TIMES expression
+    (20) expression -> expression . DIVIDE expression
+    (21) expression -> expression . EQUALS expression
+    (22) expression -> expression . NOT_EQUALS expression
+    (23) expression -> expression . LESS_EQUALS expression
+    (24) expression -> expression . LESS_THAN expression
+    (25) expression -> expression . GREATER_EQUALS expression
+    (26) expression -> expression . GREATER_THAN expression
+
+    AND             reduce using rule 21 (expression -> expression EQUALS expression .)
+    OR              reduce using rule 21 (expression -> expression EQUALS expression .)
+    EQUALS          reduce using rule 21 (expression -> expression EQUALS expression .)
+    NOT_EQUALS      reduce using rule 21 (expression -> expression EQUALS expression .)
+    IF              reduce using rule 21 (expression -> expression EQUALS expression .)
+    STRING_LITERAL  reduce using rule 21 (expression -> expression EQUALS expression .)
+    RIGHT_BRACE     reduce using rule 21 (expression -> expression EQUALS expression .)
+    RIGHT_BRACKET   reduce using rule 21 (expression -> expression EQUALS expression .)
+    PLUS            shift and go to state 44
+    MINUS           shift and go to state 48
+    TIMES           shift and go to state 49
+    DIVIDE          shift and go to state 51
+    LESS_EQUALS     shift and go to state 54
+    LESS_THAN       shift and go to state 47
+    GREATER_EQUALS  shift and go to state 55
+    GREATER_THAN    shift and go to state 53
+
+  ! PLUS            [ reduce using rule 21 (expression -> expression EQUALS expression .) ]
+  ! MINUS           [ reduce using rule 21 (expression -> expression EQUALS expression .) ]
+  ! TIMES           [ reduce using rule 21 (expression -> expression EQUALS expression .) ]
+  ! DIVIDE          [ reduce using rule 21 (expression -> expression EQUALS expression .) ]
+  ! LESS_EQUALS     [ reduce using rule 21 (expression -> expression EQUALS expression .) ]
+  ! LESS_THAN       [ reduce using rule 21 (expression -> expression EQUALS expression .) ]
+  ! GREATER_EQUALS  [ reduce using rule 21 (expression -> expression EQUALS expression .) ]
+  ! GREATER_THAN    [ reduce using rule 21 (expression -> expression EQUALS expression .) ]
+  ! AND             [ shift and go to state 52 ]
+  ! OR              [ shift and go to state 50 ]
+  ! EQUALS          [ shift and go to state 46 ]
+  ! NOT_EQUALS      [ shift and go to state 45 ]
+
+
+state 67
+
+    (24) expression -> expression LESS_THAN expression .
+    (15) expression -> expression . AND expression
+    (16) expression -> expression . OR expression
+    (17) expression -> expression . PLUS expression
+    (18) expression -> expression . MINUS expression
+    (19) expression -> expression . TIMES expression
+    (20) expression -> expression . DIVIDE expression
+    (21) expression -> expression . EQUALS expression
+    (22) expression -> expression . NOT_EQUALS expression
+    (23) expression -> expression . LESS_EQUALS expression
+    (24) expression -> expression . LESS_THAN expression
+    (25) expression -> expression . GREATER_EQUALS expression
+    (26) expression -> expression . GREATER_THAN expression
+
+    AND             reduce using rule 24 (expression -> expression LESS_THAN expression .)
+    OR              reduce using rule 24 (expression -> expression LESS_THAN expression .)
+    EQUALS          reduce using rule 24 (expression -> expression LESS_THAN expression .)
+    NOT_EQUALS      reduce using rule 24 (expression -> expression LESS_THAN expression .)
+    LESS_EQUALS     reduce using rule 24 (expression -> expression LESS_THAN expression .)
+    LESS_THAN       reduce using rule 24 (expression -> expression LESS_THAN expression .)
+    GREATER_EQUALS  reduce using rule 24 (expression -> expression LESS_THAN expression .)
+    GREATER_THAN    reduce using rule 24 (expression -> expression LESS_THAN expression .)
+    IF              reduce using rule 24 (expression -> expression LESS_THAN expression .)
+    STRING_LITERAL  reduce using rule 24 (expression -> expression LESS_THAN expression .)
+    RIGHT_BRACE     reduce using rule 24 (expression -> expression LESS_THAN expression .)
+    RIGHT_BRACKET   reduce using rule 24 (expression -> expression LESS_THAN expression .)
+    PLUS            shift and go to state 44
+    MINUS           shift and go to state 48
+    TIMES           shift and go to state 49
+    DIVIDE          shift and go to state 51
+
+  ! PLUS            [ reduce using rule 24 (expression -> expression LESS_THAN expression .) ]
+  ! MINUS           [ reduce using rule 24 (expression -> expression LESS_THAN expression .) ]
+  ! TIMES           [ reduce using rule 24 (expression -> expression LESS_THAN expression .) ]
+  ! DIVIDE          [ reduce using rule 24 (expression -> expression LESS_THAN expression .) ]
+  ! AND             [ shift and go to state 52 ]
+  ! OR              [ shift and go to state 50 ]
+  ! EQUALS          [ shift and go to state 46 ]
+  ! NOT_EQUALS      [ shift and go to state 45 ]
+  ! LESS_EQUALS     [ shift and go to state 54 ]
+  ! LESS_THAN       [ shift and go to state 47 ]
+  ! GREATER_EQUALS  [ shift and go to state 55 ]
+  ! GREATER_THAN    [ shift and go to state 53 ]
+
+
+state 68
+
+    (18) expression -> expression MINUS expression .
+    (15) expression -> expression . AND expression
+    (16) expression -> expression . OR expression
+    (17) expression -> expression . PLUS expression
+    (18) expression -> expression . MINUS expression
+    (19) expression -> expression . TIMES expression
+    (20) expression -> expression . DIVIDE expression
+    (21) expression -> expression . EQUALS expression
+    (22) expression -> expression . NOT_EQUALS expression
+    (23) expression -> expression . LESS_EQUALS expression
+    (24) expression -> expression . LESS_THAN expression
+    (25) expression -> expression . GREATER_EQUALS expression
+    (26) expression -> expression . GREATER_THAN expression
+
+    AND             reduce using rule 18 (expression -> expression MINUS expression .)
+    OR              reduce using rule 18 (expression -> expression MINUS expression .)
+    PLUS            reduce using rule 18 (expression -> expression MINUS expression .)
+    MINUS           reduce using rule 18 (expression -> expression MINUS expression .)
+    EQUALS          reduce using rule 18 (expression -> expression MINUS expression .)
+    NOT_EQUALS      reduce using rule 18 (expression -> expression MINUS expression .)
+    LESS_EQUALS     reduce using rule 18 (expression -> expression MINUS expression .)
+    LESS_THAN       reduce using rule 18 (expression -> expression MINUS expression .)
+    GREATER_EQUALS  reduce using rule 18 (expression -> expression MINUS expression .)
+    GREATER_THAN    reduce using rule 18 (expression -> expression MINUS expression .)
+    IF              reduce using rule 18 (expression -> expression MINUS expression .)
+    STRING_LITERAL  reduce using rule 18 (expression -> expression MINUS expression .)
+    RIGHT_BRACE     reduce using rule 18 (expression -> expression MINUS expression .)
+    RIGHT_BRACKET   reduce using rule 18 (expression -> expression MINUS expression .)
+    TIMES           shift and go to state 49
+    DIVIDE          shift and go to state 51
+
+  ! TIMES           [ reduce using rule 18 (expression -> expression MINUS expression .) ]
+  ! DIVIDE          [ reduce using rule 18 (expression -> expression MINUS expression .) ]
+  ! AND             [ shift and go to state 52 ]
+  ! OR              [ shift and go to state 50 ]
+  ! PLUS            [ shift and go to state 44 ]
+  ! MINUS           [ shift and go to state 48 ]
+  ! EQUALS          [ shift and go to state 46 ]
+  ! NOT_EQUALS      [ shift and go to state 45 ]
+  ! LESS_EQUALS     [ shift and go to state 54 ]
+  ! LESS_THAN       [ shift and go to state 47 ]
+  ! GREATER_EQUALS  [ shift and go to state 55 ]
+  ! GREATER_THAN    [ shift and go to state 53 ]
+
+
+state 69
+
+    (19) expression -> expression TIMES expression .
+    (15) expression -> expression . AND expression
+    (16) expression -> expression . OR expression
+    (17) expression -> expression . PLUS expression
+    (18) expression -> expression . MINUS expression
+    (19) expression -> expression . TIMES expression
+    (20) expression -> expression . DIVIDE expression
+    (21) expression -> expression . EQUALS expression
+    (22) expression -> expression . NOT_EQUALS expression
+    (23) expression -> expression . LESS_EQUALS expression
+    (24) expression -> expression . LESS_THAN expression
+    (25) expression -> expression . GREATER_EQUALS expression
+    (26) expression -> expression . GREATER_THAN expression
+
+    AND             reduce using rule 19 (expression -> expression TIMES expression .)
+    OR              reduce using rule 19 (expression -> expression TIMES expression .)
+    PLUS            reduce using rule 19 (expression -> expression TIMES expression .)
+    MINUS           reduce using rule 19 (expression -> expression TIMES expression .)
+    TIMES           reduce using rule 19 (expression -> expression TIMES expression .)
+    DIVIDE          reduce using rule 19 (expression -> expression TIMES expression .)
+    EQUALS          reduce using rule 19 (expression -> expression TIMES expression .)
+    NOT_EQUALS      reduce using rule 19 (expression -> expression TIMES expression .)
+    LESS_EQUALS     reduce using rule 19 (expression -> expression TIMES expression .)
+    LESS_THAN       reduce using rule 19 (expression -> expression TIMES expression .)
+    GREATER_EQUALS  reduce using rule 19 (expression -> expression TIMES expression .)
+    GREATER_THAN    reduce using rule 19 (expression -> expression TIMES expression .)
+    IF              reduce using rule 19 (expression -> expression TIMES expression .)
+    STRING_LITERAL  reduce using rule 19 (expression -> expression TIMES expression .)
+    RIGHT_BRACE     reduce using rule 19 (expression -> expression TIMES expression .)
+    RIGHT_BRACKET   reduce using rule 19 (expression -> expression TIMES expression .)
+
+  ! AND             [ shift and go to state 52 ]
+  ! OR              [ shift and go to state 50 ]
+  ! PLUS            [ shift and go to state 44 ]
+  ! MINUS           [ shift and go to state 48 ]
+  ! TIMES           [ shift and go to state 49 ]
+  ! DIVIDE          [ shift and go to state 51 ]
+  ! EQUALS          [ shift and go to state 46 ]
+  ! NOT_EQUALS      [ shift and go to state 45 ]
+  ! LESS_EQUALS     [ shift and go to state 54 ]
+  ! LESS_THAN       [ shift and go to state 47 ]
+  ! GREATER_EQUALS  [ shift and go to state 55 ]
+  ! GREATER_THAN    [ shift and go to state 53 ]
+
+
+state 70
+
+    (16) expression -> expression OR expression .
+    (15) expression -> expression . AND expression
+    (16) expression -> expression . OR expression
+    (17) expression -> expression . PLUS expression
+    (18) expression -> expression . MINUS expression
+    (19) expression -> expression . TIMES expression
+    (20) expression -> expression . DIVIDE expression
+    (21) expression -> expression . EQUALS expression
+    (22) expression -> expression . NOT_EQUALS expression
+    (23) expression -> expression . LESS_EQUALS expression
+    (24) expression -> expression . LESS_THAN expression
+    (25) expression -> expression . GREATER_EQUALS expression
+    (26) expression -> expression . GREATER_THAN expression
+
+    OR              reduce using rule 16 (expression -> expression OR expression .)
+    IF              reduce using rule 16 (expression -> expression OR expression .)
+    STRING_LITERAL  reduce using rule 16 (expression -> expression OR expression .)
+    RIGHT_BRACE     reduce using rule 16 (expression -> expression OR expression .)
+    RIGHT_BRACKET   reduce using rule 16 (expression -> expression OR expression .)
+    AND             shift and go to state 52
+    PLUS            shift and go to state 44
+    MINUS           shift and go to state 48
+    TIMES           shift and go to state 49
+    DIVIDE          shift and go to state 51
+    EQUALS          shift and go to state 46
+    NOT_EQUALS      shift and go to state 45
+    LESS_EQUALS     shift and go to state 54
+    LESS_THAN       shift and go to state 47
+    GREATER_EQUALS  shift and go to state 55
+    GREATER_THAN    shift and go to state 53
+
+  ! AND             [ reduce using rule 16 (expression -> expression OR expression .) ]
+  ! PLUS            [ reduce using rule 16 (expression -> expression OR expression .) ]
+  ! MINUS           [ reduce using rule 16 (expression -> expression OR expression .) ]
+  ! TIMES           [ reduce using rule 16 (expression -> expression OR expression .) ]
+  ! DIVIDE          [ reduce using rule 16 (expression -> expression OR expression .) ]
+  ! EQUALS          [ reduce using rule 16 (expression -> expression OR expression .) ]
+  ! NOT_EQUALS      [ reduce using rule 16 (expression -> expression OR expression .) ]
+  ! LESS_EQUALS     [ reduce using rule 16 (expression -> expression OR expression .) ]
+  ! LESS_THAN       [ reduce using rule 16 (expression -> expression OR expression .) ]
+  ! GREATER_EQUALS  [ reduce using rule 16 (expression -> expression OR expression .) ]
+  ! GREATER_THAN    [ reduce using rule 16 (expression -> expression OR expression .) ]
+  ! OR              [ shift and go to state 50 ]
+
+
+state 71
+
+    (20) expression -> expression DIVIDE expression .
+    (15) expression -> expression . AND expression
+    (16) expression -> expression . OR expression
+    (17) expression -> expression . PLUS expression
+    (18) expression -> expression . MINUS expression
+    (19) expression -> expression . TIMES expression
+    (20) expression -> expression . DIVIDE expression
+    (21) expression -> expression . EQUALS expression
+    (22) expression -> expression . NOT_EQUALS expression
+    (23) expression -> expression . LESS_EQUALS expression
+    (24) expression -> expression . LESS_THAN expression
+    (25) expression -> expression . GREATER_EQUALS expression
+    (26) expression -> expression . GREATER_THAN expression
+
+    AND             reduce using rule 20 (expression -> expression DIVIDE expression .)
+    OR              reduce using rule 20 (expression -> expression DIVIDE expression .)
+    PLUS            reduce using rule 20 (expression -> expression DIVIDE expression .)
+    MINUS           reduce using rule 20 (expression -> expression DIVIDE expression .)
+    TIMES           reduce using rule 20 (expression -> expression DIVIDE expression .)
+    DIVIDE          reduce using rule 20 (expression -> expression DIVIDE expression .)
+    EQUALS          reduce using rule 20 (expression -> expression DIVIDE expression .)
+    NOT_EQUALS      reduce using rule 20 (expression -> expression DIVIDE expression .)
+    LESS_EQUALS     reduce using rule 20 (expression -> expression DIVIDE expression .)
+    LESS_THAN       reduce using rule 20 (expression -> expression DIVIDE expression .)
+    GREATER_EQUALS  reduce using rule 20 (expression -> expression DIVIDE expression .)
+    GREATER_THAN    reduce using rule 20 (expression -> expression DIVIDE expression .)
+    IF              reduce using rule 20 (expression -> expression DIVIDE expression .)
+    STRING_LITERAL  reduce using rule 20 (expression -> expression DIVIDE expression .)
+    RIGHT_BRACE     reduce using rule 20 (expression -> expression DIVIDE expression .)
+    RIGHT_BRACKET   reduce using rule 20 (expression -> expression DIVIDE expression .)
+
+  ! AND             [ shift and go to state 52 ]
+  ! OR              [ shift and go to state 50 ]
+  ! PLUS            [ shift and go to state 44 ]
+  ! MINUS           [ shift and go to state 48 ]
+  ! TIMES           [ shift and go to state 49 ]
+  ! DIVIDE          [ shift and go to state 51 ]
+  ! EQUALS          [ shift and go to state 46 ]
+  ! NOT_EQUALS      [ shift and go to state 45 ]
+  ! LESS_EQUALS     [ shift and go to state 54 ]
+  ! LESS_THAN       [ shift and go to state 47 ]
+  ! GREATER_EQUALS  [ shift and go to state 55 ]
+  ! GREATER_THAN    [ shift and go to state 53 ]
+
+
+state 72
+
+    (15) expression -> expression AND expression .
+    (15) expression -> expression . AND expression
+    (16) expression -> expression . OR expression
+    (17) expression -> expression . PLUS expression
+    (18) expression -> expression . MINUS expression
+    (19) expression -> expression . TIMES expression
+    (20) expression -> expression . DIVIDE expression
+    (21) expression -> expression . EQUALS expression
+    (22) expression -> expression . NOT_EQUALS expression
+    (23) expression -> expression . LESS_EQUALS expression
+    (24) expression -> expression . LESS_THAN expression
+    (25) expression -> expression . GREATER_EQUALS expression
+    (26) expression -> expression . GREATER_THAN expression
+
+    AND             reduce using rule 15 (expression -> expression AND expression .)
+    OR              reduce using rule 15 (expression -> expression AND expression .)
+    IF              reduce using rule 15 (expression -> expression AND expression .)
+    STRING_LITERAL  reduce using rule 15 (expression -> expression AND expression .)
+    RIGHT_BRACE     reduce using rule 15 (expression -> expression AND expression .)
+    RIGHT_BRACKET   reduce using rule 15 (expression -> expression AND expression .)
+    PLUS            shift and go to state 44
+    MINUS           shift and go to state 48
+    TIMES           shift and go to state 49
+    DIVIDE          shift and go to state 51
+    EQUALS          shift and go to state 46
+    NOT_EQUALS      shift and go to state 45
+    LESS_EQUALS     shift and go to state 54
+    LESS_THAN       shift and go to state 47
+    GREATER_EQUALS  shift and go to state 55
+    GREATER_THAN    shift and go to state 53
+
+  ! PLUS            [ reduce using rule 15 (expression -> expression AND expression .) ]
+  ! MINUS           [ reduce using rule 15 (expression -> expression AND expression .) ]
+  ! TIMES           [ reduce using rule 15 (expression -> expression AND expression .) ]
+  ! DIVIDE          [ reduce using rule 15 (expression -> expression AND expression .) ]
+  ! EQUALS          [ reduce using rule 15 (expression -> expression AND expression .) ]
+  ! NOT_EQUALS      [ reduce using rule 15 (expression -> expression AND expression .) ]
+  ! LESS_EQUALS     [ reduce using rule 15 (expression -> expression AND expression .) ]
+  ! LESS_THAN       [ reduce using rule 15 (expression -> expression AND expression .) ]
+  ! GREATER_EQUALS  [ reduce using rule 15 (expression -> expression AND expression .) ]
+  ! GREATER_THAN    [ reduce using rule 15 (expression -> expression AND expression .) ]
+  ! AND             [ shift and go to state 52 ]
+  ! OR              [ shift and go to state 50 ]
+
+
+state 73
+
+    (26) expression -> expression GREATER_THAN expression .
+    (15) expression -> expression . AND expression
+    (16) expression -> expression . OR expression
+    (17) expression -> expression . PLUS expression
+    (18) expression -> expression . MINUS expression
+    (19) expression -> expression . TIMES expression
+    (20) expression -> expression . DIVIDE expression
+    (21) expression -> expression . EQUALS expression
+    (22) expression -> expression . NOT_EQUALS expression
+    (23) expression -> expression . LESS_EQUALS expression
+    (24) expression -> expression . LESS_THAN expression
+    (25) expression -> expression . GREATER_EQUALS expression
+    (26) expression -> expression . GREATER_THAN expression
+
+    AND             reduce using rule 26 (expression -> expression GREATER_THAN expression .)
+    OR              reduce using rule 26 (expression -> expression GREATER_THAN expression .)
+    EQUALS          reduce using rule 26 (expression -> expression GREATER_THAN expression .)
+    NOT_EQUALS      reduce using rule 26 (expression -> expression GREATER_THAN expression .)
+    LESS_EQUALS     reduce using rule 26 (expression -> expression GREATER_THAN expression .)
+    LESS_THAN       reduce using rule 26 (expression -> expression GREATER_THAN expression .)
+    GREATER_EQUALS  reduce using rule 26 (expression -> expression GREATER_THAN expression .)
+    GREATER_THAN    reduce using rule 26 (expression -> expression GREATER_THAN expression .)
+    IF              reduce using rule 26 (expression -> expression GREATER_THAN expression .)
+    STRING_LITERAL  reduce using rule 26 (expression -> expression GREATER_THAN expression .)
+    RIGHT_BRACE     reduce using rule 26 (expression -> expression GREATER_THAN expression .)
+    RIGHT_BRACKET   reduce using rule 26 (expression -> expression GREATER_THAN expression .)
+    PLUS            shift and go to state 44
+    MINUS           shift and go to state 48
+    TIMES           shift and go to state 49
+    DIVIDE          shift and go to state 51
+
+  ! PLUS            [ reduce using rule 26 (expression -> expression GREATER_THAN expression .) ]
+  ! MINUS           [ reduce using rule 26 (expression -> expression GREATER_THAN expression .) ]
+  ! TIMES           [ reduce using rule 26 (expression -> expression GREATER_THAN expression .) ]
+  ! DIVIDE          [ reduce using rule 26 (expression -> expression GREATER_THAN expression .) ]
+  ! AND             [ shift and go to state 52 ]
+  ! OR              [ shift and go to state 50 ]
+  ! EQUALS          [ shift and go to state 46 ]
+  ! NOT_EQUALS      [ shift and go to state 45 ]
+  ! LESS_EQUALS     [ shift and go to state 54 ]
+  ! LESS_THAN       [ shift and go to state 47 ]
+  ! GREATER_EQUALS  [ shift and go to state 55 ]
+  ! GREATER_THAN    [ shift and go to state 53 ]
+
+
+state 74
+
+    (23) expression -> expression LESS_EQUALS expression .
+    (15) expression -> expression . AND expression
+    (16) expression -> expression . OR expression
+    (17) expression -> expression . PLUS expression
+    (18) expression -> expression . MINUS expression
+    (19) expression -> expression . TIMES expression
+    (20) expression -> expression . DIVIDE expression
+    (21) expression -> expression . EQUALS expression
+    (22) expression -> expression . NOT_EQUALS expression
+    (23) expression -> expression . LESS_EQUALS expression
+    (24) expression -> expression . LESS_THAN expression
+    (25) expression -> expression . GREATER_EQUALS expression
+    (26) expression -> expression . GREATER_THAN expression
+
+    AND             reduce using rule 23 (expression -> expression LESS_EQUALS expression .)
+    OR              reduce using rule 23 (expression -> expression LESS_EQUALS expression .)
+    EQUALS          reduce using rule 23 (expression -> expression LESS_EQUALS expression .)
+    NOT_EQUALS      reduce using rule 23 (expression -> expression LESS_EQUALS expression .)
+    LESS_EQUALS     reduce using rule 23 (expression -> expression LESS_EQUALS expression .)
+    LESS_THAN       reduce using rule 23 (expression -> expression LESS_EQUALS expression .)
+    GREATER_EQUALS  reduce using rule 23 (expression -> expression LESS_EQUALS expression .)
+    GREATER_THAN    reduce using rule 23 (expression -> expression LESS_EQUALS expression .)
+    IF              reduce using rule 23 (expression -> expression LESS_EQUALS expression .)
+    STRING_LITERAL  reduce using rule 23 (expression -> expression LESS_EQUALS expression .)
+    RIGHT_BRACE     reduce using rule 23 (expression -> expression LESS_EQUALS expression .)
+    RIGHT_BRACKET   reduce using rule 23 (expression -> expression LESS_EQUALS expression .)
+    PLUS            shift and go to state 44
+    MINUS           shift and go to state 48
+    TIMES           shift and go to state 49
+    DIVIDE          shift and go to state 51
+
+  ! PLUS            [ reduce using rule 23 (expression -> expression LESS_EQUALS expression .) ]
+  ! MINUS           [ reduce using rule 23 (expression -> expression LESS_EQUALS expression .) ]
+  ! TIMES           [ reduce using rule 23 (expression -> expression LESS_EQUALS expression .) ]
+  ! DIVIDE          [ reduce using rule 23 (expression -> expression LESS_EQUALS expression .) ]
+  ! AND             [ shift and go to state 52 ]
+  ! OR              [ shift and go to state 50 ]
+  ! EQUALS          [ shift and go to state 46 ]
+  ! NOT_EQUALS      [ shift and go to state 45 ]
+  ! LESS_EQUALS     [ shift and go to state 54 ]
+  ! LESS_THAN       [ shift and go to state 47 ]
+  ! GREATER_EQUALS  [ shift and go to state 55 ]
+  ! GREATER_THAN    [ shift and go to state 53 ]
+
+
+state 75
+
+    (25) expression -> expression GREATER_EQUALS expression .
+    (15) expression -> expression . AND expression
+    (16) expression -> expression . OR expression
+    (17) expression -> expression . PLUS expression
+    (18) expression -> expression . MINUS expression
+    (19) expression -> expression . TIMES expression
+    (20) expression -> expression . DIVIDE expression
+    (21) expression -> expression . EQUALS expression
+    (22) expression -> expression . NOT_EQUALS expression
+    (23) expression -> expression . LESS_EQUALS expression
+    (24) expression -> expression . LESS_THAN expression
+    (25) expression -> expression . GREATER_EQUALS expression
+    (26) expression -> expression . GREATER_THAN expression
+
+    AND             reduce using rule 25 (expression -> expression GREATER_EQUALS expression .)
+    OR              reduce using rule 25 (expression -> expression GREATER_EQUALS expression .)
+    EQUALS          reduce using rule 25 (expression -> expression GREATER_EQUALS expression .)
+    NOT_EQUALS      reduce using rule 25 (expression -> expression GREATER_EQUALS expression .)
+    LESS_EQUALS     reduce using rule 25 (expression -> expression GREATER_EQUALS expression .)
+    LESS_THAN       reduce using rule 25 (expression -> expression GREATER_EQUALS expression .)
+    GREATER_EQUALS  reduce using rule 25 (expression -> expression GREATER_EQUALS expression .)
+    GREATER_THAN    reduce using rule 25 (expression -> expression GREATER_EQUALS expression .)
+    IF              reduce using rule 25 (expression -> expression GREATER_EQUALS expression .)
+    STRING_LITERAL  reduce using rule 25 (expression -> expression GREATER_EQUALS expression .)
+    RIGHT_BRACE     reduce using rule 25 (expression -> expression GREATER_EQUALS expression .)
+    RIGHT_BRACKET   reduce using rule 25 (expression -> expression GREATER_EQUALS expression .)
+    PLUS            shift and go to state 44
+    MINUS           shift and go to state 48
+    TIMES           shift and go to state 49
+    DIVIDE          shift and go to state 51
+
+  ! PLUS            [ reduce using rule 25 (expression -> expression GREATER_EQUALS expression .) ]
+  ! MINUS           [ reduce using rule 25 (expression -> expression GREATER_EQUALS expression .) ]
+  ! TIMES           [ reduce using rule 25 (expression -> expression GREATER_EQUALS expression .) ]
+  ! DIVIDE          [ reduce using rule 25 (expression -> expression GREATER_EQUALS expression .) ]
+  ! AND             [ shift and go to state 52 ]
+  ! OR              [ shift and go to state 50 ]
+  ! EQUALS          [ shift and go to state 46 ]
+  ! NOT_EQUALS      [ shift and go to state 45 ]
+  ! LESS_EQUALS     [ shift and go to state 54 ]
+  ! LESS_THAN       [ shift and go to state 47 ]
+  ! GREATER_EQUALS  [ shift and go to state 55 ]
+  ! GREATER_THAN    [ shift and go to state 53 ]
+
+
+state 76
+
+    (8) question -> STRING_LITERAL IDENTIFIER COLON type ASSIGN . expression
+    (11) expression -> . LEFT_BRACKET expression RIGHT_BRACKET
+    (12) expression -> . IDENTIFIER
+    (13) expression -> . NOT expression
+    (14) expression -> . MINUS expression
+    (15) expression -> . expression AND expression
+    (16) expression -> . expression OR expression
+    (17) expression -> . expression PLUS expression
+    (18) expression -> . expression MINUS expression
+    (19) expression -> . expression TIMES expression
+    (20) expression -> . expression DIVIDE expression
+    (21) expression -> . expression EQUALS expression
+    (22) expression -> . expression NOT_EQUALS expression
+    (23) expression -> . expression LESS_EQUALS expression
+    (24) expression -> . expression LESS_THAN expression
+    (25) expression -> . expression GREATER_EQUALS expression
+    (26) expression -> . expression GREATER_THAN expression
+    (27) expression -> . FALSE
+    (28) expression -> . TRUE
+    (29) expression -> . DATE_LITERAL
+    (30) expression -> . INTEGER_LITERAL
+    (31) expression -> . DECIMAL_LITERAL
+    (32) expression -> . currency DECIMAL_LITERAL
+    (33) expression -> . currency INTEGER_LITERAL
+    (34) expression -> . STRING_LITERAL
+    (35) currency -> . DOLLAR
+    (36) currency -> . RUBLE
+
+    LEFT_BRACKET    shift and go to state 30
+    IDENTIFIER      shift and go to state 34
+    NOT             shift and go to state 27
+    MINUS           shift and go to state 25
+    FALSE           shift and go to state 35
+    TRUE            shift and go to state 32
+    DATE_LITERAL    shift and go to state 24
+    INTEGER_LITERAL shift and go to state 26
+    DECIMAL_LITERAL shift and go to state 31
+    STRING_LITERAL  shift and go to state 28
+    DOLLAR          shift and go to state 29
+    RUBLE           shift and go to state 23
+
+    expression                     shift and go to state 77
+    currency                       shift and go to state 22
+
+state 77
+
+    (8) question -> STRING_LITERAL IDENTIFIER COLON type ASSIGN expression .
+    (15) expression -> expression . AND expression
+    (16) expression -> expression . OR expression
+    (17) expression -> expression . PLUS expression
+    (18) expression -> expression . MINUS expression
+    (19) expression -> expression . TIMES expression
+    (20) expression -> expression . DIVIDE expression
+    (21) expression -> expression . EQUALS expression
+    (22) expression -> expression . NOT_EQUALS expression
+    (23) expression -> expression . LESS_EQUALS expression
+    (24) expression -> expression . LESS_THAN expression
+    (25) expression -> expression . GREATER_EQUALS expression
+    (26) expression -> expression . GREATER_THAN expression
+
+    IF              reduce using rule 8 (question -> STRING_LITERAL IDENTIFIER COLON type ASSIGN expression .)
+    STRING_LITERAL  reduce using rule 8 (question -> STRING_LITERAL IDENTIFIER COLON type ASSIGN expression .)
+    RIGHT_BRACE     reduce using rule 8 (question -> STRING_LITERAL IDENTIFIER COLON type ASSIGN expression .)
+    AND             shift and go to state 52
+    OR              shift and go to state 50
+    PLUS            shift and go to state 44
+    MINUS           shift and go to state 48
+    TIMES           shift and go to state 49
+    DIVIDE          shift and go to state 51
+    EQUALS          shift and go to state 46
+    NOT_EQUALS      shift and go to state 45
+    LESS_EQUALS     shift and go to state 54
+    LESS_THAN       shift and go to state 47
+    GREATER_EQUALS  shift and go to state 55
+    GREATER_THAN    shift and go to state 53
+
diff --git a/ql/parser/parser.py b/ql/parser/parser.py
new file mode 100644
index 0000000..d962a0f
--- /dev/null
+++ b/ql/parser/parser.py
@@ -0,0 +1,319 @@
+from ply.yacc import yacc
+
+from ql.ast.nodes.expressions.binary_operators.addition_operator import AdditionOperatorNode
+from ql.ast.nodes.expressions.binary_operators.and_operator import AndOperatorNode
+from ql.ast.nodes.expressions.binary_operators.division_operator import DivisionOperatorNode
+from ql.ast.nodes.expressions.binary_operators.equals_operator import EqualsOperatorNode
+from ql.ast.nodes.expressions.binary_operators.greater_equals_operator import GreaterEqualsOperatorNode
+from ql.ast.nodes.expressions.binary_operators.greater_than_operator import GreaterThanOperatorNode
+from ql.ast.nodes.expressions.binary_operators.less_equals_operator import LessEqualsOperatorNode
+from ql.ast.nodes.expressions.binary_operators.less_than_operator import LessThanOperatorNode
+from ql.ast.nodes.expressions.binary_operators.multiplication_operator import MultiplicationOperatorNode
+from ql.ast.nodes.expressions.binary_operators.not_equals_operator import NotEqualsOperatorNode
+from ql.ast.nodes.expressions.binary_operators.or_operator import OrOperatorNode
+from ql.ast.nodes.expressions.binary_operators.subtraction_operator import SubtractionOperatorNode
+from ql.ast.nodes.expressions.literals.boolean_literal import BooleanNode
+from ql.ast.nodes.expressions.literals.date_literal import DateNode
+from ql.ast.nodes.expressions.literals.decimal_literal import DecimalNode
+from ql.ast.nodes.expressions.literals.integer_literal import IntegerNode
+from ql.ast.nodes.expressions.literals.money_literal import MoneyNode
+from ql.ast.nodes.expressions.literals.string_literal import StringNode
+from ql.ast.nodes.expressions.unary_operators.negation_operator import NegationOperatorNode
+from ql.ast.nodes.expressions.unary_operators.negative_operator import NegativeOperatorNode
+from ql.ast.nodes.expressions.variable import VariableNode
+from ql.ast.nodes.statements.form_statement import FormNode
+from ql.ast.nodes.statements.if_statement import IfNode
+from ql.ast.nodes.statements.question_statement import QuestionNode
+from ql.parser.lexer import QLLexer
+from ql.parser.metadata import Metadata
+from ql.types.boolean import QLBoolean
+from ql.types.date import QLDate
+from ql.types.decimal import QLDecimal
+from ql.types.integer import QLInteger
+from ql.types.money import QLMoney
+from ql.types.string import QLString
+from ql.types.undefined import QLUndefined
+
+
+class QLParser:
+    def __init__(self):
+        self.__errors = []
+        self.__tokens = QLLexer.tokens
+        self.__parser = None
+        self.__precedence = (
+            ('left', 'OR'),
+            ('left', 'AND'),
+            ('nonassoc', 'EQUALS', 'NOT_EQUALS'),
+            ('nonassoc', 'LESS_EQUALS', 'LESS_THAN', 'GREATER_EQUALS', 'GREATER_THAN'),
+            ('left', 'PLUS', 'MINUS'),
+            ('left', 'TIMES', 'DIVIDE'),
+            ('right', 'NOT'),
+        )
+
+    @property
+    def errors(self):
+        return self.__errors
+
+    @property
+    def tokens(self):
+        return self.__tokens
+
+    @property
+    def parser(self):
+        return self.__parser
+
+    @property
+    def precedence(self):
+        return self.__precedence
+
+    def build(self):
+        self.__parser = yacc(module=self)
+
+    def parse(self, data, lexer):
+        self.__errors = []
+        return self.parser.parse(data, lexer)
+
+    # Grammar
+    @staticmethod
+    def p_form(production):
+        """form : FORM IDENTIFIER block"""
+        production[0] = FormNode(Metadata(production.lineno(1)), production[3], production[2])
+
+    @staticmethod
+    def p_block(production):
+        """block : LEFT_BRACE statements RIGHT_BRACE"""
+        production[0] = production[2]
+
+    # Statements
+    @staticmethod
+    def p_statements(production):
+        """statements   : statement statements
+                        | statement"""
+        if len(production) == 3:
+            production[0] = [production[1]] + production[2]
+        elif len(production) == 2:
+            production[0] = [production[1]]
+
+    @staticmethod
+    def p_statement(production):
+        """statement    : if
+                        | question"""
+        production[0] = production[1]
+
+    # Questions
+    @staticmethod
+    def p_question(production):
+        """question : STRING_LITERAL IDENTIFIER COLON type"""
+        production[0] = QuestionNode(Metadata(production.lineno(1)), production[1], production[2],
+                                     production[4], production[4].get_literal_node(production[4]()), False)
+
+    @staticmethod
+    def p_question_computed(production):
+        """question : STRING_LITERAL IDENTIFIER COLON type ASSIGN expression"""
+        production[0] = QuestionNode(Metadata(production.lineno(1)), production[1], production[2],
+                                     production[4], production[6], True)
+
+    # Control flow
+    @staticmethod
+    def p_if(production):
+        """if : IF condition block"""
+        production[0] = IfNode(Metadata(production.lineno(1)), production[3], production[2])
+
+    @staticmethod
+    def p_condition(production):
+        """condition : LEFT_BRACKET expression RIGHT_BRACKET"""
+        production[0] = production[2]
+
+    # Expressions
+    @staticmethod
+    def p_parenthesis(production):
+        """expression : LEFT_BRACKET expression RIGHT_BRACKET"""
+        production[0] = production[2]
+
+    @staticmethod
+    def p_variable(production):
+        """expression : IDENTIFIER"""
+        production[0] = VariableNode(Metadata(production.lineno(1)), QLUndefined, production[1],
+                                     QLUndefined())
+
+    # Unary operators
+    @staticmethod
+    def p_not(production):
+        """expression : NOT expression"""
+        production[0] = NegationOperatorNode(Metadata(production.lineno(1)), QLBoolean,
+                                             production[2], QLUndefined())
+
+    @staticmethod
+    def p_negative(production):
+        """expression : MINUS expression"""
+        production[0] = NegativeOperatorNode(Metadata(production.lineno(1)), QLUndefined,
+                                             production[2], QLUndefined())
+
+    # Binary operators
+    @staticmethod
+    def p_and(production):
+        """expression : expression AND expression"""
+        production[0] = AndOperatorNode(Metadata(production.lineno(2)), QLBoolean, production[1],
+                                        production[3], QLUndefined())
+
+    @staticmethod
+    def p_or(production):
+        """expression : expression OR expression"""
+        production[0] = OrOperatorNode(Metadata(production.lineno(2)), QLBoolean, production[1],
+                                       production[3], QLUndefined())
+
+    @staticmethod
+    def p_plus(production):
+        """expression : expression PLUS expression"""
+        production[0] = AdditionOperatorNode(Metadata(production.lineno(2)), QLUndefined,
+                                             production[1], production[3], QLUndefined())
+
+    @staticmethod
+    def p_minus(production):
+        """expression : expression MINUS expression"""
+        production[0] = SubtractionOperatorNode(Metadata(production.lineno(2)), QLUndefined,
+                                                production[1], production[3], QLUndefined())
+
+    @staticmethod
+    def p_times(production):
+        """expression : expression TIMES expression"""
+        production[0] = MultiplicationOperatorNode(Metadata(production.lineno(2)), QLUndefined,
+                                                   production[1], production[3], QLUndefined())
+
+    @staticmethod
+    def p_divide(production):
+        """expression : expression DIVIDE expression"""
+        production[0] = DivisionOperatorNode(Metadata(production.lineno(2)), QLUndefined,
+                                             production[1], production[3], QLUndefined())
+
+    @staticmethod
+    def p_equals(production):
+        """expression : expression EQUALS expression"""
+        production[0] = EqualsOperatorNode(Metadata(production.lineno(2)), QLBoolean,
+                                           production[1], production[3], QLUndefined())
+
+    @staticmethod
+    def p_not_equals(production):
+        """expression : expression NOT_EQUALS expression"""
+        production[0] = NotEqualsOperatorNode(Metadata(production.lineno(2)), QLBoolean,
+                                              production[1], production[3], QLUndefined())
+
+    @staticmethod
+    def p_less_equals(production):
+        """expression : expression LESS_EQUALS expression"""
+        production[0] = LessEqualsOperatorNode(Metadata(production.lineno(2)), QLBoolean,
+                                               production[1], production[3], QLUndefined())
+
+    @staticmethod
+    def p_less_than(production):
+        """expression : expression LESS_THAN expression"""
+        production[0] = LessThanOperatorNode(Metadata(production.lineno(2)), QLBoolean,
+                                             production[1], production[3], QLUndefined())
+
+    @staticmethod
+    def p_greater_equals(production):
+        """expression : expression GREATER_EQUALS expression"""
+        production[0] = GreaterEqualsOperatorNode(Metadata(production.lineno(2)), QLBoolean,
+                                                  production[1], production[3], QLUndefined())
+
+    @staticmethod
+    def p_greater_than(production):
+        """expression : expression GREATER_THAN expression"""
+        production[0] = GreaterThanOperatorNode(Metadata(production.lineno(2)), QLBoolean,
+                                                production[1], production[3], QLUndefined())
+
+    # Literals
+    @staticmethod
+    def p_boolean_literal(production):
+        """expression   : FALSE
+                        | TRUE"""
+        production[0] = BooleanNode(Metadata(production.lineno(1)), QLBoolean, QLBoolean(production[1]))
+
+    @staticmethod
+    def p_date_literal(production):
+        """expression : DATE_LITERAL"""
+        day, month, year = production[1]
+        production[0] = DateNode(Metadata(production.lineno(1)), QLDate, QLDate(day, month, year))
+
+    @staticmethod
+    def p_integer_literal(production):
+        """expression : INTEGER_LITERAL"""
+        production[0] = IntegerNode(Metadata(production.lineno(1)), QLInteger, QLInteger(production[1]))
+
+    @staticmethod
+    def p_decimal_literal(production):
+        """expression : DECIMAL_LITERAL"""
+        production[0] = DecimalNode(Metadata(production.lineno(1)), QLDecimal, QLDecimal(production[1]))
+
+    @staticmethod
+    def p_money_literal(production):
+        """expression   : currency DECIMAL_LITERAL
+                        | currency INTEGER_LITERAL"""
+        production[0] = MoneyNode(Metadata(production.lineno(1)), QLMoney,
+                                  QLMoney(production[2], production[1]))
+
+    @staticmethod
+    def p_string_literal(production):
+        """expression : STRING_LITERAL"""
+        production[0] = StringNode(Metadata(production.lineno(1)), QLString, QLString([1]))
+
+    # Currencies
+    @staticmethod
+    def p_currency(production):
+        """currency : DOLLAR
+                    | RUBLE"""
+        production[0] = production[1]
+
+    # Types
+    @staticmethod
+    def p_boolean(production):
+        """type : BOOLEAN"""
+        production[0] = QLBoolean
+
+    @staticmethod
+    def p_decimal(production):
+        """type : DECIMAL"""
+        production[0] = QLDecimal
+
+    @staticmethod
+    def p_string(production):
+        """type : STRING"""
+        production[0] = QLString
+
+    @staticmethod
+    def p_date(production):
+        """type : DATE"""
+        production[0] = QLDate
+
+    @staticmethod
+    def p_money(production):
+        """type : MONEY"""
+        production[0] = QLMoney
+
+    @staticmethod
+    def p_integer(production):
+        """type : INTEGER"""
+        production[0] = QLInteger
+
+    # Error
+    def p_error(self, production):
+        if production is None:
+            self.errors.append('Syntax error.')
+        else:
+            self.errors.append('Syntax error at line {}, token={}.'.format(production.lineno, production.type))
+
+    def p_form_label(self, production):
+        """form : FORM LEFT_BRACE"""
+        self.errors.append('Missing form identifier at line {}.'.format(production.lineno(1)))
+
+    def p_empty_form(self, production):
+        """form : FORM IDENTIFIER LEFT_BRACE RIGHT_BRACE"""
+        self.errors.append('Empty form at line {}.'.format(production.lineno(1)))
+
+    def p_empty_if(self, production):
+        """statement : IF condition LEFT_BRACE RIGHT_BRACE"""
+        self.errors.append('Empty if block at line {}.'.format(production.lineno(1)))
+
+    def p_empty_condition(self, production):
+        """condition : LEFT_BRACKET RIGHT_BRACKET"""
+        self.errors.append('Empty conditional at line {}.'.format(production.lineno(1)))
diff --git a/ql/parser/parsetab.py b/ql/parser/parsetab.py
new file mode 100644
index 0000000..b978ef8
--- /dev/null
+++ b/ql/parser/parsetab.py
@@ -0,0 +1,76 @@
+
+# parsetab.py
+# This file is automatically generated. Do not edit.
+# pylint: disable=W,C,R
+_tabversion = '3.10'
+
+_lr_method = 'LALR'
+
+_lr_signature = 'leftORleftANDnonassocEQUALSNOT_EQUALSnonassocLESS_EQUALSLESS_THANGREATER_EQUALSGREATER_THANleftPLUSMINUSleftTIMESDIVIDErightNOTAND ASSIGN BOOLEAN COLON DATE DATE_LITERAL DECIMAL DECIMAL_LITERAL DIVIDE DOLLAR EQUALS FALSE FORM GREATER_EQUALS GREATER_THAN IDENTIFIER IF INTEGER INTEGER_LITERAL LEFT_BRACE LEFT_BRACKET LESS_EQUALS LESS_THAN MINUS MONEY NOT NOT_EQUALS OR PLUS RIGHT_BRACE RIGHT_BRACKET RUBLE STRING STRING_LITERAL TIMES TRUEform : FORM IDENTIFIER blockblock : LEFT_BRACE statements RIGHT_BRACEstatements   : statement statements\n                        | statementstatement    : if\n                        | questionquestion : STRING_LITERAL IDENTIFIER COLON typequestion : STRING_LITERAL IDENTIFIER COLON type ASSIGN expressionif : IF condition blockcondition : LEFT_BRACKET expression RIGHT_BRACKETexpression : LEFT_BRACKET expression RIGHT_BRACKETexpression : IDENTIFIERexpression : NOT expressionexpression : MINUS expressionexpression : expression AND expressionexpression : expression OR expressionexpression : expression PLUS expressionexpression : expression MINUS expressionexpression : expression TIMES expressionexpression : expression DIVIDE expressionexpression : expression EQUALS expressionexpression : expression NOT_EQUALS expressionexpression : expression LESS_EQUALS expressionexpression : expression LESS_THAN expressionexpression : expression GREATER_EQUALS expressionexpression : expression GREATER_THAN expressionexpression   : FALSE\n                        | TRUEexpression : DATE_LITERALexpression : INTEGER_LITERALexpression : DECIMAL_LITERALexpression   : currency DECIMAL_LITERAL\n                        | currency INTEGER_LITERALexpression : STRING_LITERALcurrency : DOLLAR\n                    | RUBLEtype : BOOLEANtype : DECIMALtype : STRINGtype : DATEtype : MONEYtype : INTEGERform : FORM LEFT_BRACEform : FORM IDENTIFIER LEFT_BRACE RIGHT_BRACEstatement : IF condition LEFT_BRACE RIGHT_BRACEcondition : LEFT_BRACKET RIGHT_BRACKET'
+    
+_lr_action_items = {'RIGHT_BRACKET':([17,24,26,28,31,32,33,34,35,38,39,40,41,42,63,64,65,66,67,68,69,70,71,72,73,74,75,],[21,-29,-30,-34,-31,-28,43,-12,-27,-32,-33,-14,-13,63,-11,-17,-22,-21,-24,-18,-19,-16,-20,-15,-26,-23,-25,]),'TRUE':([17,25,27,30,44,45,46,47,48,49,50,51,52,53,54,55,76,],[32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,]),'LEFT_BRACE':([1,3,16,21,43,],[4,5,19,-46,-10,]),'RUBLE':([17,25,27,30,44,45,46,47,48,49,50,51,52,53,54,55,76,],[23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,]),'DATE_LITERAL':([17,25,27,30,44,45,46,47,48,49,50,51,52,53,54,55,76,],[24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,]),'MINUS':([17,24,25,26,27,28,30,31,32,33,34,35,38,39,40,41,42,44,45,46,47,48,49,50,51,52,53,54,55,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,],[25,-29,25,-30,25,-34,25,-31,-28,48,-12,-27,-32,-33,-14,-13,48,25,25,25,25,25,25,25,25,25,25,25,25,-11,-17,48,48,48,-18,-19,48,-20,48,48,48,48,25,48,]),'INTEGER_LITERAL':([17,22,23,25,27,29,30,44,45,46,47,48,49,50,51,52,53,54,55,76,],[26,39,-36,26,26,-35,26,26,26,26,26,26,26,26,26,26,26,26,26,26,]),'TIMES':([24,26,28,31,32,33,34,35,38,39,40,41,42,63,64,65,66,67,68,69,70,71,72,73,74,75,77,],[-29,-30,-34,-31,-28,49,-12,-27,-32,-33,49,-13,49,-11,49,49,49,49,49,-19,49,-20,49,49,49,49,49,]),'NOT':([17,25,27,30,44,45,46,47,48,49,50,51,52,53,54,55,76,],[27,27,27,27,27,27,27,27,27,27,27,27,27,27,27,27,27,]),'DOLLAR':([17,25,27,30,44,45,46,47,48,49,50,51,52,53,54,55,76,],[29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,]),'MONEY':([36,],[60,]),'INTEGER':([36,],[61,]),'AND':([24,26,28,31,32,33,34,35,38,39,40,41,42,63,64,65,66,67,68,69,70,71,72,73,74,75,77,],[-29,-30,-34,-31,-28,52,-12,-27,-32,-33,-14,-13,52,-11,-17,-22,-21,-24,-18,-19,52,-20,-15,-26,-23,-25,52,]),'NOT_EQUALS':([24,26,28,31,32,33,34,35,38,39,40,41,42,63,64,65,66,67,68,69,70,71,72,73,74,75,77,],[-29,-30,-34,-31,-28,45,-12,-27,-32,-33,-14,-13,45,-11,-17,None,None,-24,-18,-19,45,-20,45,-26,-23,-25,45,]),'ASSIGN':([56,57,58,59,60,61,62,],[-40,-38,-39,76,-41,-42,-37,]),'BOOLEAN':([36,],[62,]),'FORM':([0,],[1,]),'IF':([5,7,8,10,14,19,20,24,26,28,31,32,34,35,37,38,39,40,41,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,77,],[11,-5,-6,11,-2,11,-9,-29,-30,-34,-31,-28,-12,-27,-45,-32,-33,-14,-13,-40,-38,-39,-7,-41,-42,-37,-11,-17,-22,-21,-24,-18,-19,-16,-20,-15,-26,-23,-25,-8,]),'LEFT_BRACKET':([11,17,25,27,30,44,45,46,47,48,49,50,51,52,53,54,55,76,],[17,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,]),'PLUS':([24,26,28,31,32,33,34,35,38,39,40,41,42,63,64,65,66,67,68,69,70,71,72,73,74,75,77,],[-29,-30,-34,-31,-28,44,-12,-27,-32,-33,-14,-13,44,-11,-17,44,44,44,-18,-19,44,-20,44,44,44,44,44,]),'$end':([2,4,6,13,14,],[0,-43,-1,-44,-2,]),'EQUALS':([24,26,28,31,32,33,34,35,38,39,40,41,42,63,64,65,66,67,68,69,70,71,72,73,74,75,77,],[-29,-30,-34,-31,-28,46,-12,-27,-32,-33,-14,-13,46,-11,-17,None,None,-24,-18,-19,46,-20,46,-26,-23,-25,46,]),'IDENTIFIER':([1,12,17,25,27,30,44,45,46,47,48,49,50,51,52,53,54,55,76,],[3,18,34,34,34,34,34,34,34,34,34,34,34,34,34,34,34,34,34,]),'LESS_THAN':([24,26,28,31,32,33,34,35,38,39,40,41,42,63,64,65,66,67,68,69,70,71,72,73,74,75,77,],[-29,-30,-34,-31,-28,47,-12,-27,-32,-33,-14,-13,47,-11,-17,47,47,None,-18,-19,47,-20,47,None,None,None,47,]),'STRING':([36,],[58,]),'COLON':([18,],[36,]),'DATE':([36,],[56,]),'STRING_LITERAL':([5,7,8,10,14,17,19,20,24,25,26,27,28,30,31,32,34,35,37,38,39,40,41,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,],[12,-5,-6,12,-2,28,12,-9,-29,28,-30,28,-34,28,-31,-28,-12,-27,-45,-32,-33,-14,-13,28,28,28,28,28,28,28,28,28,28,28,28,-40,-38,-39,-7,-41,-42,-37,-11,-17,-22,-21,-24,-18,-19,-16,-20,-15,-26,-23,-25,28,-8,]),'DECIMAL_LITERAL':([17,22,23,25,27,29,30,44,45,46,47,48,49,50,51,52,53,54,55,76,],[31,38,-36,31,31,-35,31,31,31,31,31,31,31,31,31,31,31,31,31,31,]),'OR':([24,26,28,31,32,33,34,35,38,39,40,41,42,63,64,65,66,67,68,69,70,71,72,73,74,75,77,],[-29,-30,-34,-31,-28,50,-12,-27,-32,-33,-14,-13,50,-11,-17,-22,-21,-24,-18,-19,-16,-20,-15,-26,-23,-25,50,]),'FALSE':([17,25,27,30,44,45,46,47,48,49,50,51,52,53,54,55,76,],[35,35,35,35,35,35,35,35,35,35,35,35,35,35,35,35,35,]),'DECIMAL':([36,],[57,]),'DIVIDE':([24,26,28,31,32,33,34,35,38,39,40,41,42,63,64,65,66,67,68,69,70,71,72,73,74,75,77,],[-29,-30,-34,-31,-28,51,-12,-27,-32,-33,51,-13,51,-11,51,51,51,51,51,-19,51,-20,51,51,51,51,51,]),'LESS_EQUALS':([24,26,28,31,32,33,34,35,38,39,40,41,42,63,64,65,66,67,68,69,70,71,72,73,74,75,77,],[-29,-30,-34,-31,-28,54,-12,-27,-32,-33,-14,-13,54,-11,-17,54,54,None,-18,-19,54,-20,54,None,None,None,54,]),'RIGHT_BRACE':([5,7,8,9,10,14,15,19,20,24,26,28,31,32,34,35,37,38,39,40,41,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,77,],[13,-5,-6,14,-4,-2,-3,37,-9,-29,-30,-34,-31,-28,-12,-27,-45,-32,-33,-14,-13,-40,-38,-39,-7,-41,-42,-37,-11,-17,-22,-21,-24,-18,-19,-16,-20,-15,-26,-23,-25,-8,]),'GREATER_EQUALS':([24,26,28,31,32,33,34,35,38,39,40,41,42,63,64,65,66,67,68,69,70,71,72,73,74,75,77,],[-29,-30,-34,-31,-28,55,-12,-27,-32,-33,-14,-13,55,-11,-17,55,55,None,-18,-19,55,-20,55,None,None,None,55,]),'GREATER_THAN':([24,26,28,31,32,33,34,35,38,39,40,41,42,63,64,65,66,67,68,69,70,71,72,73,74,75,77,],[-29,-30,-34,-31,-28,53,-12,-27,-32,-33,-14,-13,53,-11,-17,53,53,None,-18,-19,53,-20,53,None,None,None,53,]),}
+
+_lr_action = {}
+for _k, _v in _lr_action_items.items():
+   for _x,_y in zip(_v[0],_v[1]):
+      if not _x in _lr_action:  _lr_action[_x] = {}
+      _lr_action[_x][_k] = _y
+del _lr_action_items
+
+_lr_goto_items = {'if':([5,10,19,],[7,7,7,]),'condition':([11,],[16,]),'question':([5,10,19,],[8,8,8,]),'expression':([17,25,27,30,44,45,46,47,48,49,50,51,52,53,54,55,76,],[33,40,41,42,64,65,66,67,68,69,70,71,72,73,74,75,77,]),'currency':([17,25,27,30,44,45,46,47,48,49,50,51,52,53,54,55,76,],[22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,]),'type':([36,],[59,]),'statements':([5,10,19,],[9,15,9,]),'statement':([5,10,19,],[10,10,10,]),'form':([0,],[2,]),'block':([3,16,],[6,20,]),}
+
+_lr_goto = {}
+for _k, _v in _lr_goto_items.items():
+   for _x, _y in zip(_v[0], _v[1]):
+       if not _x in _lr_goto: _lr_goto[_x] = {}
+       _lr_goto[_x][_k] = _y
+del _lr_goto_items
+_lr_productions = [
+  ("S' -> form","S'",1,None,None,None),
+  ('form -> FORM IDENTIFIER block','form',3,'p_form','parser.py',78),
+  ('block -> LEFT_BRACE statements RIGHT_BRACE','block',3,'p_block','parser.py',83),
+  ('statements -> statement statements','statements',2,'p_statements','parser.py',89),
+  ('statements -> statement','statements',1,'p_statements','parser.py',90),
+  ('statement -> if','statement',1,'p_statement','parser.py',98),
+  ('statement -> question','statement',1,'p_statement','parser.py',99),
+  ('question -> STRING_LITERAL IDENTIFIER COLON type','question',4,'p_question','parser.py',105),
+  ('question -> STRING_LITERAL IDENTIFIER COLON type ASSIGN expression','question',6,'p_question_computed','parser.py',111),
+  ('if -> IF condition block','if',3,'p_if','parser.py',118),
+  ('condition -> LEFT_BRACKET expression RIGHT_BRACKET','condition',3,'p_condition','parser.py',123),
+  ('expression -> LEFT_BRACKET expression RIGHT_BRACKET','expression',3,'p_parenthesis','parser.py',129),
+  ('expression -> IDENTIFIER','expression',1,'p_variable','parser.py',134),
+  ('expression -> NOT expression','expression',2,'p_not','parser.py',141),
+  ('expression -> MINUS expression','expression',2,'p_negative','parser.py',147),
+  ('expression -> expression AND expression','expression',3,'p_and','parser.py',154),
+  ('expression -> expression OR expression','expression',3,'p_or','parser.py',160),
+  ('expression -> expression PLUS expression','expression',3,'p_plus','parser.py',166),
+  ('expression -> expression MINUS expression','expression',3,'p_minus','parser.py',172),
+  ('expression -> expression TIMES expression','expression',3,'p_times','parser.py',178),
+  ('expression -> expression DIVIDE expression','expression',3,'p_divide','parser.py',184),
+  ('expression -> expression EQUALS expression','expression',3,'p_equals','parser.py',190),
+  ('expression -> expression NOT_EQUALS expression','expression',3,'p_not_equals','parser.py',196),
+  ('expression -> expression LESS_EQUALS expression','expression',3,'p_less_equals','parser.py',202),
+  ('expression -> expression LESS_THAN expression','expression',3,'p_less_than','parser.py',208),
+  ('expression -> expression GREATER_EQUALS expression','expression',3,'p_greater_equals','parser.py',214),
+  ('expression -> expression GREATER_THAN expression','expression',3,'p_greater_than','parser.py',220),
+  ('expression -> FALSE','expression',1,'p_boolean_literal','parser.py',227),
+  ('expression -> TRUE','expression',1,'p_boolean_literal','parser.py',228),
+  ('expression -> DATE_LITERAL','expression',1,'p_date_literal','parser.py',233),
+  ('expression -> INTEGER_LITERAL','expression',1,'p_integer_literal','parser.py',238),
+  ('expression -> DECIMAL_LITERAL','expression',1,'p_decimal_literal','parser.py',243),
+  ('expression -> currency DECIMAL_LITERAL','expression',2,'p_money_literal','parser.py',248),
+  ('expression -> currency INTEGER_LITERAL','expression',2,'p_money_literal','parser.py',249),
+  ('expression -> STRING_LITERAL','expression',1,'p_string_literal','parser.py',255),
+  ('currency -> DOLLAR','currency',1,'p_currency','parser.py',261),
+  ('currency -> RUBLE','currency',1,'p_currency','parser.py',262),
+  ('type -> BOOLEAN','type',1,'p_boolean','parser.py',268),
+  ('type -> DECIMAL','type',1,'p_decimal','parser.py',273),
+  ('type -> STRING','type',1,'p_string','parser.py',278),
+  ('type -> DATE','type',1,'p_date','parser.py',283),
+  ('type -> MONEY','type',1,'p_money','parser.py',288),
+  ('type -> INTEGER','type',1,'p_integer','parser.py',293),
+  ('form -> FORM LEFT_BRACE','form',2,'p_form_label','parser.py',305),
+  ('form -> FORM IDENTIFIER LEFT_BRACE RIGHT_BRACE','form',4,'p_empty_form','parser.py',309),
+  ('statement -> IF condition LEFT_BRACE RIGHT_BRACE','statement',4,'p_empty_if','parser.py',313),
+  ('condition -> LEFT_BRACKET RIGHT_BRACKET','condition',2,'p_empty_condition','parser.py',317),
+]
diff --git a/ql/test/__pycache__/test.cpython-35.pyc b/ql/test/__pycache__/test.cpython-35.pyc
new file mode 100644
index 0000000..2eb18b1
--- /dev/null
+++ b/ql/test/__pycache__/test.cpython-35.pyc
diff --git a/ql/test/expression_evaluation/__pycache__/test_expression_evaluation.cpython-35.pyc b/ql/test/expression_evaluation/__pycache__/test_expression_evaluation.cpython-35.pyc
new file mode 100644
index 0000000..2104122
--- /dev/null
+++ b/ql/test/expression_evaluation/__pycache__/test_expression_evaluation.cpython-35.pyc
diff --git a/ql/test/expression_evaluation/test_expression_evaluation.py b/ql/test/expression_evaluation/test_expression_evaluation.py
new file mode 100644
index 0000000..067ebda
--- /dev/null
+++ b/ql/test/expression_evaluation/test_expression_evaluation.py
@@ -0,0 +1,49 @@
+from json import loads
+
+from ql.ast.extractors.extractor import extract_gui_model
+from ql.ast.extractors.extractor import extract_identifier_types
+from ql.ast.visitors.expression_evaluator import ExpressionEvaluator
+from ql.ast.visitors.type_visitor import TypeVisitor
+from ql.types.boolean import QLBoolean
+from ql.types.date import QLDate
+from ql.types.decimal import QLDecimal
+from ql.types.integer import QLInteger
+from ql.types.money import QLMoney
+from ql.types.string import QLString
+from ql.test.test import Test
+
+
+class TestExpressionEvaluation(Test):
+    def __init__(self, directory, lexer, parser):
+        super(TestExpressionEvaluation, self).__init__('expression evaluation', directory)
+        self.__lexer = lexer
+        self.__parser = parser
+
+    def test_file(self, file):
+        ast = self.__parser.parse(file, self.__lexer.lexer)
+
+        if not self.__parser.errors:
+            TypeVisitor(extract_identifier_types(ast)).visit(ast)
+            model = extract_gui_model(ast)
+            result_type, result_value = file.split('\n')[0].split()[-2:]
+            correct_result = None
+
+            if result_type == 'QLBoolean' and result_value == 'True':
+                correct_result = QLBoolean(True)
+            elif result_type == 'QLBoolean':
+                correct_result = QLBoolean()
+            elif result_type == 'QLDate':
+                day, month, year = loads(result_value)
+                correct_result = QLDate(day, month, year)
+            elif result_type == 'QLDecimal':
+                correct_result = QLDecimal(result_value)
+            elif result_type == 'QLInteger':
+                correct_result = QLInteger(result_value)
+            elif result_type == 'QLMoney':
+                correct_result = QLMoney(result_value)
+            elif result_type == 'QLString':
+                correct_result = QLString(result_value)
+
+            expression_evaluator = ExpressionEvaluator(model)
+            expression_evaluator.visit(ast.block[0].answer)
+            return bool(expression_evaluator.result == correct_result)
diff --git a/ql/test/expression_evaluation/valid/test001.ql b/ql/test/expression_evaluation/valid/test001.ql
new file mode 100644
index 0000000..fc72525
--- /dev/null
+++ b/ql/test/expression_evaluation/valid/test001.ql
@@ -0,0 +1,5 @@
+// Correct result type and result value: QLBoolean False
+form label {
+    "Question"
+    id : boolean = False
+}
\ No newline at end of file
diff --git a/ql/test/expression_evaluation/valid/test002.ql b/ql/test/expression_evaluation/valid/test002.ql
new file mode 100644
index 0000000..f4d722b
--- /dev/null
+++ b/ql/test/expression_evaluation/valid/test002.ql
@@ -0,0 +1,5 @@
+// Correct result type and result value: QLBoolean True
+form label {
+    "Question"
+    id : boolean = True
+}
\ No newline at end of file
diff --git a/ql/test/expression_evaluation/valid/test003.ql b/ql/test/expression_evaluation/valid/test003.ql
new file mode 100644
index 0000000..2998f36
--- /dev/null
+++ b/ql/test/expression_evaluation/valid/test003.ql
@@ -0,0 +1,5 @@
+// Correct result type and result value: QLBoolean True
+form label {
+    "Question"
+    id : boolean = not False
+}
\ No newline at end of file
diff --git a/ql/test/expression_evaluation/valid/test004.ql b/ql/test/expression_evaluation/valid/test004.ql
new file mode 100644
index 0000000..fcfd827
--- /dev/null
+++ b/ql/test/expression_evaluation/valid/test004.ql
@@ -0,0 +1,5 @@
+// Correct result type and result value: QLBoolean False
+form label {
+    "Question"
+    id : boolean = not True
+}
\ No newline at end of file
diff --git a/ql/test/expression_evaluation/valid/test005.ql b/ql/test/expression_evaluation/valid/test005.ql
new file mode 100644
index 0000000..0ee8989
--- /dev/null
+++ b/ql/test/expression_evaluation/valid/test005.ql
@@ -0,0 +1,5 @@
+// Correct result type and result value: QLBoolean True
+form label {
+    "Question"
+    id : boolean = False == False
+}
\ No newline at end of file
diff --git a/ql/test/expression_evaluation/valid/test006.ql b/ql/test/expression_evaluation/valid/test006.ql
new file mode 100644
index 0000000..70f15f2
--- /dev/null
+++ b/ql/test/expression_evaluation/valid/test006.ql
@@ -0,0 +1,5 @@
+// Correct result type and result value: QLBoolean False
+form label {
+    "Question"
+    id : boolean = False == True
+}
\ No newline at end of file
diff --git a/ql/test/expression_evaluation/valid/test007.ql b/ql/test/expression_evaluation/valid/test007.ql
new file mode 100644
index 0000000..76f37b0
--- /dev/null
+++ b/ql/test/expression_evaluation/valid/test007.ql
@@ -0,0 +1,5 @@
+// Correct result type and result value: QLBoolean False
+form label {
+    "Question"
+    id : boolean = True == False
+}
\ No newline at end of file
diff --git a/ql/test/expression_evaluation/valid/test008.ql b/ql/test/expression_evaluation/valid/test008.ql
new file mode 100644
index 0000000..f6d5710
--- /dev/null
+++ b/ql/test/expression_evaluation/valid/test008.ql
@@ -0,0 +1,5 @@
+// Correct result type and result value: QLBoolean True
+form label {
+    "Question"
+    id : boolean = True == True
+}
\ No newline at end of file
diff --git a/ql/test/expression_evaluation/valid/test009.ql b/ql/test/expression_evaluation/valid/test009.ql
new file mode 100644
index 0000000..6a3d465
--- /dev/null
+++ b/ql/test/expression_evaluation/valid/test009.ql
@@ -0,0 +1,5 @@
+// Correct result type and result value: QLBoolean False
+form label {
+    "Question"
+    id : boolean = False != False
+}
\ No newline at end of file
diff --git a/ql/test/expression_evaluation/valid/test010.ql b/ql/test/expression_evaluation/valid/test010.ql
new file mode 100644
index 0000000..e398dde
--- /dev/null
+++ b/ql/test/expression_evaluation/valid/test010.ql
@@ -0,0 +1,5 @@
+// Correct result type and result value: QLBoolean True
+form label {
+    "Question"
+    id : boolean = False != True
+}
\ No newline at end of file
diff --git a/ql/test/expression_evaluation/valid/test011.ql b/ql/test/expression_evaluation/valid/test011.ql
new file mode 100644
index 0000000..3a7cbd1
--- /dev/null
+++ b/ql/test/expression_evaluation/valid/test011.ql
@@ -0,0 +1,5 @@
+// Correct result type and result value: QLBoolean True
+form label {
+    "Question"
+    id : boolean = True != False
+}
\ No newline at end of file
diff --git a/ql/test/expression_evaluation/valid/test012.ql b/ql/test/expression_evaluation/valid/test012.ql
new file mode 100644
index 0000000..2a7185e
--- /dev/null
+++ b/ql/test/expression_evaluation/valid/test012.ql
@@ -0,0 +1,5 @@
+// Correct result type and result value: QLBoolean False
+form label {
+    "Question"
+    id : boolean = True != True
+}
\ No newline at end of file
diff --git a/ql/test/expression_evaluation/valid/test013.ql b/ql/test/expression_evaluation/valid/test013.ql
new file mode 100644
index 0000000..bed71a2
--- /dev/null
+++ b/ql/test/expression_evaluation/valid/test013.ql
@@ -0,0 +1,5 @@
+// Correct result type and result value: QLDate [1,1,2018]
+form label {
+    "Question"
+    id : boolean = date(1,1,2018)
+}
\ No newline at end of file
diff --git a/ql/test/expression_evaluation/valid/test014.ql b/ql/test/expression_evaluation/valid/test014.ql
new file mode 100644
index 0000000..4d4413d
--- /dev/null
+++ b/ql/test/expression_evaluation/valid/test014.ql
@@ -0,0 +1,5 @@
+// Correct result type and result value: QLBoolean True
+form label {
+    "Question"
+    id : boolean = date(1,1,2018) == date(1,1,2018)
+}
\ No newline at end of file
diff --git a/ql/test/expression_evaluation/valid/test015.ql b/ql/test/expression_evaluation/valid/test015.ql
new file mode 100644
index 0000000..06a75ba
--- /dev/null
+++ b/ql/test/expression_evaluation/valid/test015.ql
@@ -0,0 +1,5 @@
+// Correct result type and result value: QLBoolean False
+form label {
+    "Question"
+    id : boolean = date(1,1,2018) == date(1,1,2017)
+}
\ No newline at end of file
diff --git a/ql/test/expression_evaluation/valid/test016.ql b/ql/test/expression_evaluation/valid/test016.ql
new file mode 100644
index 0000000..3cb4215
--- /dev/null
+++ b/ql/test/expression_evaluation/valid/test016.ql
@@ -0,0 +1,5 @@
+// Correct result type and result value: QLBoolean False
+form label {
+    "Question"
+    id : boolean = date(1,1,109) == date(1,1,2018)
+}
\ No newline at end of file
diff --git a/ql/test/expression_evaluation/valid/test017.ql b/ql/test/expression_evaluation/valid/test017.ql
new file mode 100644
index 0000000..d4a3bbf
--- /dev/null
+++ b/ql/test/expression_evaluation/valid/test017.ql
@@ -0,0 +1,5 @@
+// Correct result type and result value: QLBoolean False
+form label {
+    "Question"
+    id : boolean = date(1,1,2018) == date(1,7,2018)
+}
\ No newline at end of file
diff --git a/ql/test/expression_evaluation/valid/test018.ql b/ql/test/expression_evaluation/valid/test018.ql
new file mode 100644
index 0000000..38f80ea
--- /dev/null
+++ b/ql/test/expression_evaluation/valid/test018.ql
@@ -0,0 +1,5 @@
+// Correct result type and result value: QLBoolean False
+form label {
+    "Question"
+    id : boolean = date(1,3,2018) == date(1,1,2018)
+}
\ No newline at end of file
diff --git a/ql/test/expression_evaluation/valid/test019.ql b/ql/test/expression_evaluation/valid/test019.ql
new file mode 100644
index 0000000..8d797b5
--- /dev/null
+++ b/ql/test/expression_evaluation/valid/test019.ql
@@ -0,0 +1,5 @@
+// Correct result type and result value: QLBoolean False
+form label {
+    "Question"
+    id : boolean = date(1,1,2018) == date(5,1,2018)
+}
\ No newline at end of file
diff --git a/ql/test/expression_evaluation/valid/test020.ql b/ql/test/expression_evaluation/valid/test020.ql
new file mode 100644
index 0000000..5d401cf
--- /dev/null
+++ b/ql/test/expression_evaluation/valid/test020.ql
@@ -0,0 +1,5 @@
+// Correct result type and result value: QLBoolean False
+form label {
+    "Question"
+    id : boolean = date(21,1,2018) == date(1,1,2018)
+}
\ No newline at end of file
diff --git a/ql/test/lexing/__pycache__/test_lexing.cpython-35.pyc b/ql/test/lexing/__pycache__/test_lexing.cpython-35.pyc
new file mode 100644
index 0000000..eca2f01
--- /dev/null
+++ b/ql/test/lexing/__pycache__/test_lexing.cpython-35.pyc
diff --git a/ql/test/lexing/invalid/test001.ql b/ql/test/lexing/invalid/test001.ql
new file mode 100644
index 0000000..37bf0fd
--- /dev/null
+++ b/ql/test/lexing/invalid/test001.ql
@@ -0,0 +1,2 @@
+// Illegal character (`)
+`
\ No newline at end of file
diff --git a/ql/test/lexing/invalid/test002.ql b/ql/test/lexing/invalid/test002.ql
new file mode 100644
index 0000000..b691de9
--- /dev/null
+++ b/ql/test/lexing/invalid/test002.ql
@@ -0,0 +1,2 @@
+// Illegal character (~)
+~
\ No newline at end of file
diff --git a/ql/test/lexing/invalid/test003.ql b/ql/test/lexing/invalid/test003.ql
new file mode 100644
index 0000000..b75fc41
--- /dev/null
+++ b/ql/test/lexing/invalid/test003.ql
@@ -0,0 +1,2 @@
+// Illegal character (@)
+@
\ No newline at end of file
diff --git a/ql/test/lexing/invalid/test004.ql b/ql/test/lexing/invalid/test004.ql
new file mode 100644
index 0000000..9b3e1f7
--- /dev/null
+++ b/ql/test/lexing/invalid/test004.ql
@@ -0,0 +1,2 @@
+// Illegal character (#)
+#
\ No newline at end of file
diff --git a/ql/test/lexing/invalid/test005.ql b/ql/test/lexing/invalid/test005.ql
new file mode 100644
index 0000000..9bd5fc4
--- /dev/null
+++ b/ql/test/lexing/invalid/test005.ql
@@ -0,0 +1,2 @@
+// Illegal character (€)
+€
\ No newline at end of file
diff --git a/ql/test/lexing/invalid/test006.ql b/ql/test/lexing/invalid/test006.ql
new file mode 100644
index 0000000..a7c1336
--- /dev/null
+++ b/ql/test/lexing/invalid/test006.ql
@@ -0,0 +1,2 @@
+// Illegal character (%)
+%
\ No newline at end of file
diff --git a/ql/test/lexing/invalid/test007.ql b/ql/test/lexing/invalid/test007.ql
new file mode 100644
index 0000000..39cbd63
--- /dev/null
+++ b/ql/test/lexing/invalid/test007.ql
@@ -0,0 +1,2 @@
+// Illegal character (^)
+^
\ No newline at end of file
diff --git a/ql/test/lexing/invalid/test008.ql b/ql/test/lexing/invalid/test008.ql
new file mode 100644
index 0000000..82f2836
--- /dev/null
+++ b/ql/test/lexing/invalid/test008.ql
@@ -0,0 +1,2 @@
+// Illegal character (&)
+&
\ No newline at end of file
diff --git a/ql/test/lexing/invalid/test009.ql b/ql/test/lexing/invalid/test009.ql
new file mode 100644
index 0000000..e92526e
--- /dev/null
+++ b/ql/test/lexing/invalid/test009.ql
@@ -0,0 +1,2 @@
+// Illegal character (_)
+_
\ No newline at end of file
diff --git a/ql/test/lexing/invalid/test010.ql b/ql/test/lexing/invalid/test010.ql
new file mode 100644
index 0000000..30c8837
--- /dev/null
+++ b/ql/test/lexing/invalid/test010.ql
@@ -0,0 +1,2 @@
+// Illegal character ([)
+[
\ No newline at end of file
diff --git a/ql/test/lexing/invalid/test011.ql b/ql/test/lexing/invalid/test011.ql
new file mode 100644
index 0000000..f047fbc
--- /dev/null
+++ b/ql/test/lexing/invalid/test011.ql
@@ -0,0 +1,2 @@
+// Illegal character (])
+]
\ No newline at end of file
diff --git a/ql/test/lexing/invalid/test012.ql b/ql/test/lexing/invalid/test012.ql
new file mode 100644
index 0000000..81e3796
--- /dev/null
+++ b/ql/test/lexing/invalid/test012.ql
@@ -0,0 +1,2 @@
+// Illegal character (\)
+\
\ No newline at end of file
diff --git a/ql/test/lexing/invalid/test013.ql b/ql/test/lexing/invalid/test013.ql
new file mode 100644
index 0000000..0a6d02c
--- /dev/null
+++ b/ql/test/lexing/invalid/test013.ql
@@ -0,0 +1,2 @@
+// Illegal character (|)
+|
\ No newline at end of file
diff --git a/ql/test/lexing/invalid/test014.ql b/ql/test/lexing/invalid/test014.ql
new file mode 100644
index 0000000..48ede2c
--- /dev/null
+++ b/ql/test/lexing/invalid/test014.ql
@@ -0,0 +1,2 @@
+// Illegal character (;)
+;
\ No newline at end of file
diff --git a/ql/test/lexing/invalid/test015.ql b/ql/test/lexing/invalid/test015.ql
new file mode 100644
index 0000000..ec798a0
--- /dev/null
+++ b/ql/test/lexing/invalid/test015.ql
@@ -0,0 +1,2 @@
+// Illegal character (')
+'
\ No newline at end of file
diff --git a/ql/test/lexing/invalid/test016.ql b/ql/test/lexing/invalid/test016.ql
new file mode 100644
index 0000000..6d67365
--- /dev/null
+++ b/ql/test/lexing/invalid/test016.ql
@@ -0,0 +1,2 @@
+// Illegal character (")
+"
\ No newline at end of file
diff --git a/ql/test/lexing/invalid/test017.ql b/ql/test/lexing/invalid/test017.ql
new file mode 100644
index 0000000..d8907bd
--- /dev/null
+++ b/ql/test/lexing/invalid/test017.ql
@@ -0,0 +1,2 @@
+// Illegal character (,)
+,
\ No newline at end of file
diff --git a/ql/test/lexing/invalid/test018.ql b/ql/test/lexing/invalid/test018.ql
new file mode 100644
index 0000000..73fece7
--- /dev/null
+++ b/ql/test/lexing/invalid/test018.ql
@@ -0,0 +1,2 @@
+// Illegal character (?)
+?
\ No newline at end of file
diff --git a/ql/test/lexing/invalid/test019.ql b/ql/test/lexing/invalid/test019.ql
new file mode 100644
index 0000000..407e52e
--- /dev/null
+++ b/ql/test/lexing/invalid/test019.ql
@@ -0,0 +1,2 @@
+// Illegal characters (uppercase characters)
+A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
\ No newline at end of file
diff --git a/ql/test/lexing/test_lexing.py b/ql/test/lexing/test_lexing.py
new file mode 100644
index 0000000..978b1d7
--- /dev/null
+++ b/ql/test/lexing/test_lexing.py
@@ -0,0 +1,15 @@
+from ql.test.test import Test
+
+
+class TestLexing(Test):
+    def __init__(self, directory, lexer):
+        super(TestLexing, self).__init__('lexing', directory)
+        self.__lexer = lexer
+
+    def test_file(self, file):
+        self.__lexer.tokenize(file)
+
+        if self.__lexer.errors:
+            return False
+
+        return True
diff --git a/ql/test/lexing/valid/test001.ql b/ql/test/lexing/valid/test001.ql
new file mode 100644
index 0000000..9862fb0
--- /dev/null
+++ b/ql/test/lexing/valid/test001.ql
@@ -0,0 +1,2 @@
+// Form token
+form
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test002.ql b/ql/test/lexing/valid/test002.ql
new file mode 100644
index 0000000..2efece0
--- /dev/null
+++ b/ql/test/lexing/valid/test002.ql
@@ -0,0 +1,2 @@
+// If token
+if
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test003.ql b/ql/test/lexing/valid/test003.ql
new file mode 100644
index 0000000..dc30033
--- /dev/null
+++ b/ql/test/lexing/valid/test003.ql
@@ -0,0 +1,2 @@
+// Boolean type token
+boolean
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test004.ql b/ql/test/lexing/valid/test004.ql
new file mode 100644
index 0000000..233e652
--- /dev/null
+++ b/ql/test/lexing/valid/test004.ql
@@ -0,0 +1,2 @@
+// Date type token
+date
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test005.ql b/ql/test/lexing/valid/test005.ql
new file mode 100644
index 0000000..9d1f615
--- /dev/null
+++ b/ql/test/lexing/valid/test005.ql
@@ -0,0 +1,2 @@
+// Decimal type token
+decimal
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test006.ql b/ql/test/lexing/valid/test006.ql
new file mode 100644
index 0000000..506c72e
--- /dev/null
+++ b/ql/test/lexing/valid/test006.ql
@@ -0,0 +1,2 @@
+// Integer type token
+integer
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test007.ql b/ql/test/lexing/valid/test007.ql
new file mode 100644
index 0000000..66c665f
--- /dev/null
+++ b/ql/test/lexing/valid/test007.ql
@@ -0,0 +1,2 @@
+// Money type token
+money
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test008.ql b/ql/test/lexing/valid/test008.ql
new file mode 100644
index 0000000..3455595
--- /dev/null
+++ b/ql/test/lexing/valid/test008.ql
@@ -0,0 +1,2 @@
+// String type token
+string
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test009.ql b/ql/test/lexing/valid/test009.ql
new file mode 100644
index 0000000..123a526
--- /dev/null
+++ b/ql/test/lexing/valid/test009.ql
@@ -0,0 +1,2 @@
+// Plus token
++
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test010.ql b/ql/test/lexing/valid/test010.ql
new file mode 100644
index 0000000..ac494f7
--- /dev/null
+++ b/ql/test/lexing/valid/test010.ql
@@ -0,0 +1,2 @@
+// Minus token
+-
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test011.ql b/ql/test/lexing/valid/test011.ql
new file mode 100644
index 0000000..c53f248
--- /dev/null
+++ b/ql/test/lexing/valid/test011.ql
@@ -0,0 +1,2 @@
+// Times token
+*
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test012.ql b/ql/test/lexing/valid/test012.ql
new file mode 100644
index 0000000..195d9b9
--- /dev/null
+++ b/ql/test/lexing/valid/test012.ql
@@ -0,0 +1,2 @@
+// Divide token
+/
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test013.ql b/ql/test/lexing/valid/test013.ql
new file mode 100644
index 0000000..d1c0471
--- /dev/null
+++ b/ql/test/lexing/valid/test013.ql
@@ -0,0 +1,2 @@
+// Colon token
+:
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test014.ql b/ql/test/lexing/valid/test014.ql
new file mode 100644
index 0000000..f72179a
--- /dev/null
+++ b/ql/test/lexing/valid/test014.ql
@@ -0,0 +1,2 @@
+// Assign token
+=
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test015.ql b/ql/test/lexing/valid/test015.ql
new file mode 100644
index 0000000..09f1ea1
--- /dev/null
+++ b/ql/test/lexing/valid/test015.ql
@@ -0,0 +1,2 @@
+// Equals token
+==
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test016.ql b/ql/test/lexing/valid/test016.ql
new file mode 100644
index 0000000..9cc8e9b
--- /dev/null
+++ b/ql/test/lexing/valid/test016.ql
@@ -0,0 +1,2 @@
+// Not equals token
+!=
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test017.ql b/ql/test/lexing/valid/test017.ql
new file mode 100644
index 0000000..ce8af09
--- /dev/null
+++ b/ql/test/lexing/valid/test017.ql
@@ -0,0 +1,2 @@
+// Greater than token
+>
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test018.ql b/ql/test/lexing/valid/test018.ql
new file mode 100644
index 0000000..dad4f9c
--- /dev/null
+++ b/ql/test/lexing/valid/test018.ql
@@ -0,0 +1,2 @@
+// Greater equals token
+>=
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test019.ql b/ql/test/lexing/valid/test019.ql
new file mode 100644
index 0000000..39ec8a3
--- /dev/null
+++ b/ql/test/lexing/valid/test019.ql
@@ -0,0 +1,2 @@
+// Less than token
+<
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test020.ql b/ql/test/lexing/valid/test020.ql
new file mode 100644
index 0000000..902ec15
--- /dev/null
+++ b/ql/test/lexing/valid/test020.ql
@@ -0,0 +1,2 @@
+// Less equals token
+<=
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test021.ql b/ql/test/lexing/valid/test021.ql
new file mode 100644
index 0000000..296f504
--- /dev/null
+++ b/ql/test/lexing/valid/test021.ql
@@ -0,0 +1,2 @@
+// Not token
+not
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test022.ql b/ql/test/lexing/valid/test022.ql
new file mode 100644
index 0000000..1d4fe36
--- /dev/null
+++ b/ql/test/lexing/valid/test022.ql
@@ -0,0 +1,2 @@
+// Brace tokens
+{}
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test023.ql b/ql/test/lexing/valid/test023.ql
new file mode 100644
index 0000000..3b27a60
--- /dev/null
+++ b/ql/test/lexing/valid/test023.ql
@@ -0,0 +1,2 @@
+// Bracket tokens
+()
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test024.ql b/ql/test/lexing/valid/test024.ql
new file mode 100644
index 0000000..72854c9
--- /dev/null
+++ b/ql/test/lexing/valid/test024.ql
@@ -0,0 +1,2 @@
+// Whitespace tokens
+
diff --git a/ql/test/lexing/valid/test025.ql b/ql/test/lexing/valid/test025.ql
new file mode 100644
index 0000000..ceb93d0
--- /dev/null
+++ b/ql/test/lexing/valid/test025.ql
@@ -0,0 +1,2 @@
+// Identifier token (lowercase)
+testidentifier
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test026.ql b/ql/test/lexing/valid/test026.ql
new file mode 100644
index 0000000..90589b2
--- /dev/null
+++ b/ql/test/lexing/valid/test026.ql
@@ -0,0 +1,2 @@
+// Identifier token (camelcase)
+testIdentifier
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test027.ql b/ql/test/lexing/valid/test027.ql
new file mode 100644
index 0000000..076f4b0
--- /dev/null
+++ b/ql/test/lexing/valid/test027.ql
@@ -0,0 +1,2 @@
+// Identifier token (underscore)
+test_identifier
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test028.ql b/ql/test/lexing/valid/test028.ql
new file mode 100644
index 0000000..855dd9a
--- /dev/null
+++ b/ql/test/lexing/valid/test028.ql
@@ -0,0 +1,2 @@
+// Identifier token (number)
+identifier123
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test029.ql b/ql/test/lexing/valid/test029.ql
new file mode 100644
index 0000000..1d37fa2
--- /dev/null
+++ b/ql/test/lexing/valid/test029.ql
@@ -0,0 +1,2 @@
+// Boolean literal token (false)
+False
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test030.ql b/ql/test/lexing/valid/test030.ql
new file mode 100644
index 0000000..bc70591
--- /dev/null
+++ b/ql/test/lexing/valid/test030.ql
@@ -0,0 +1,2 @@
+// Boolean literal token (true)
+True
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test031.ql b/ql/test/lexing/valid/test031.ql
new file mode 100644
index 0000000..106a0ad
--- /dev/null
+++ b/ql/test/lexing/valid/test031.ql
@@ -0,0 +1,2 @@
+// Date literal token
+date(1, 1, 2018)
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test032.ql b/ql/test/lexing/valid/test032.ql
new file mode 100644
index 0000000..51cc57a
--- /dev/null
+++ b/ql/test/lexing/valid/test032.ql
@@ -0,0 +1,2 @@
+// Date literal token
+date(99, 99, 9999)
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test033.ql b/ql/test/lexing/valid/test033.ql
new file mode 100644
index 0000000..f6a8535
--- /dev/null
+++ b/ql/test/lexing/valid/test033.ql
@@ -0,0 +1,2 @@
+// Decimal literal token
+0.0
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test034.ql b/ql/test/lexing/valid/test034.ql
new file mode 100644
index 0000000..15b2e6a
--- /dev/null
+++ b/ql/test/lexing/valid/test034.ql
@@ -0,0 +1,2 @@
+// Decimal literal token
+3.14
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test035.ql b/ql/test/lexing/valid/test035.ql
new file mode 100644
index 0000000..49616a7
--- /dev/null
+++ b/ql/test/lexing/valid/test035.ql
@@ -0,0 +1,2 @@
+// Decimal literal token
+1234567890.0987654321
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test036.ql b/ql/test/lexing/valid/test036.ql
new file mode 100644
index 0000000..86f7a4e
--- /dev/null
+++ b/ql/test/lexing/valid/test036.ql
@@ -0,0 +1,2 @@
+// Decimal literal token
+999999999999999999999999999999999999999999999999999999999999999.999999999999999999999999999999999999999999999999999999999999999
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test037.ql b/ql/test/lexing/valid/test037.ql
new file mode 100644
index 0000000..174d0ce
--- /dev/null
+++ b/ql/test/lexing/valid/test037.ql
@@ -0,0 +1,2 @@
+// Integer literal token
+0
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test038.ql b/ql/test/lexing/valid/test038.ql
new file mode 100644
index 0000000..6740489
--- /dev/null
+++ b/ql/test/lexing/valid/test038.ql
@@ -0,0 +1,2 @@
+// Integer literal token
+1234567890
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test039.ql b/ql/test/lexing/valid/test039.ql
new file mode 100644
index 0000000..d2dbc53
--- /dev/null
+++ b/ql/test/lexing/valid/test039.ql
@@ -0,0 +1,2 @@
+// String literal token
+"abcdefghijklmnopqrstuvwxyz"
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test040.ql b/ql/test/lexing/valid/test040.ql
new file mode 100644
index 0000000..306582b
--- /dev/null
+++ b/ql/test/lexing/valid/test040.ql
@@ -0,0 +1,2 @@
+// String literal token
+"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test041.ql b/ql/test/lexing/valid/test041.ql
new file mode 100644
index 0000000..84f0aff
--- /dev/null
+++ b/ql/test/lexing/valid/test041.ql
@@ -0,0 +1,2 @@
+// String literal token
+"1234567890"
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test042.ql b/ql/test/lexing/valid/test042.ql
new file mode 100644
index 0000000..d389d9f
--- /dev/null
+++ b/ql/test/lexing/valid/test042.ql
@@ -0,0 +1,2 @@
+// String literal token
+"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890"
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test043.ql b/ql/test/lexing/valid/test043.ql
new file mode 100644
index 0000000..6698694
--- /dev/null
+++ b/ql/test/lexing/valid/test043.ql
@@ -0,0 +1,2 @@
+// String literal token
+"`~!@#$%*()-=_+[]\{}|;:,./<>?"
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test044.ql b/ql/test/lexing/valid/test044.ql
new file mode 100644
index 0000000..d09b55d
--- /dev/null
+++ b/ql/test/lexing/valid/test044.ql
@@ -0,0 +1,2 @@
+// String literal token
+"\'"
\ No newline at end of file
diff --git a/ql/test/lexing/valid/test045.ql b/ql/test/lexing/valid/test045.ql
new file mode 100644
index 0000000..d85d414
--- /dev/null
+++ b/ql/test/lexing/valid/test045.ql
@@ -0,0 +1,2 @@
+// String literal token
+"\""
\ No newline at end of file
diff --git a/ql/test/parsing/__pycache__/test_parsing.cpython-35.pyc b/ql/test/parsing/__pycache__/test_parsing.cpython-35.pyc
new file mode 100644
index 0000000..4e89c3e
--- /dev/null
+++ b/ql/test/parsing/__pycache__/test_parsing.cpython-35.pyc
diff --git a/ql/test/parsing/invalid/test001.ql b/ql/test/parsing/invalid/test001.ql
new file mode 100644
index 0000000..fab17ac
--- /dev/null
+++ b/ql/test/parsing/invalid/test001.ql
@@ -0,0 +1 @@
+// Empty file
diff --git a/ql/test/parsing/invalid/test002.ql b/ql/test/parsing/invalid/test002.ql
new file mode 100644
index 0000000..d84f901
--- /dev/null
+++ b/ql/test/parsing/invalid/test002.ql
@@ -0,0 +1,3 @@
+// Empty form without label
+form {
+}
\ No newline at end of file
diff --git a/ql/test/parsing/invalid/test003.ql b/ql/test/parsing/invalid/test003.ql
new file mode 100644
index 0000000..57975a1
--- /dev/null
+++ b/ql/test/parsing/invalid/test003.ql
@@ -0,0 +1,3 @@
+// Empty form
+form testForm {
+}
\ No newline at end of file
diff --git a/ql/test/parsing/invalid/test004.ql b/ql/test/parsing/invalid/test004.ql
new file mode 100644
index 0000000..6f2fb9f
--- /dev/null
+++ b/ql/test/parsing/invalid/test004.ql
@@ -0,0 +1,5 @@
+// Form without label
+form {
+    "Question?"
+    var : boolean
+}
\ No newline at end of file
diff --git a/ql/test/parsing/invalid/test005.ql b/ql/test/parsing/invalid/test005.ql
new file mode 100644
index 0000000..5b67d6e
--- /dev/null
+++ b/ql/test/parsing/invalid/test005.ql
@@ -0,0 +1,5 @@
+// Question label without quotation marks
+form testForm {
+    question
+    var : cows
+}
\ No newline at end of file
diff --git a/ql/test/parsing/invalid/test006.ql b/ql/test/parsing/invalid/test006.ql
new file mode 100644
index 0000000..b902dc9
--- /dev/null
+++ b/ql/test/parsing/invalid/test006.ql
@@ -0,0 +1,5 @@
+// Question with invalid type
+form testForm {
+    "Question?"
+    var : cows
+}
\ No newline at end of file
diff --git a/ql/test/parsing/invalid/test007.ql b/ql/test/parsing/invalid/test007.ql
new file mode 100644
index 0000000..e16685e
--- /dev/null
+++ b/ql/test/parsing/invalid/test007.ql
@@ -0,0 +1,5 @@
+// Question identifier with quotation marks
+form testForm {
+    "Question?"
+    "var" : boolean
+}
\ No newline at end of file
diff --git a/ql/test/parsing/invalid/test018.ql b/ql/test/parsing/invalid/test018.ql
new file mode 100644
index 0000000..80deece
--- /dev/null
+++ b/ql/test/parsing/invalid/test018.ql
@@ -0,0 +1,7 @@
+// Empty if conditional
+form testForm {
+    if () {
+        "Question?"
+        id : boolean
+    }
+}
\ No newline at end of file
diff --git a/ql/test/parsing/invalid/test019.ql b/ql/test/parsing/invalid/test019.ql
new file mode 100644
index 0000000..1bde8f1
--- /dev/null
+++ b/ql/test/parsing/invalid/test019.ql
@@ -0,0 +1,5 @@
+// Empty if block
+form label {
+    if (1 == 2) {
+    }
+}
\ No newline at end of file
diff --git a/ql/test/parsing/test_parsing.py b/ql/test/parsing/test_parsing.py
new file mode 100644
index 0000000..86900f9
--- /dev/null
+++ b/ql/test/parsing/test_parsing.py
@@ -0,0 +1,16 @@
+from ql.test.test import Test
+
+
+class TestParsing(Test):
+    def __init__(self, directory, lexer, parser):
+        super(TestParsing, self).__init__('parsing', directory)
+        self.__lexer = lexer
+        self.__parser = parser
+
+    def test_file(self, file):
+        self.__parser.parse(file, self.__lexer.lexer)
+
+        if self.__parser.errors:
+            return False
+
+        return True
diff --git a/ql/test/parsing/valid/test001.ql b/ql/test/parsing/valid/test001.ql
new file mode 100644
index 0000000..aecb488
--- /dev/null
+++ b/ql/test/parsing/valid/test001.ql
@@ -0,0 +1,5 @@
+// Form with question type boolean
+form testForm {
+  "Question?"
+    var: boolean
+}
\ No newline at end of file
diff --git a/ql/test/parsing/valid/test002.ql b/ql/test/parsing/valid/test002.ql
new file mode 100644
index 0000000..89402fa
--- /dev/null
+++ b/ql/test/parsing/valid/test002.ql
@@ -0,0 +1,5 @@
+// Form with question of type date
+form testForm {
+  "Question?"
+    var: date
+}
\ No newline at end of file
diff --git a/ql/test/parsing/valid/test003.ql b/ql/test/parsing/valid/test003.ql
new file mode 100644
index 0000000..8f8f448
--- /dev/null
+++ b/ql/test/parsing/valid/test003.ql
@@ -0,0 +1,5 @@
+// Form with question of type decimal
+form testForm {
+  "Question?"
+    var: decimal
+}
\ No newline at end of file
diff --git a/ql/test/parsing/valid/test004.ql b/ql/test/parsing/valid/test004.ql
new file mode 100644
index 0000000..7d4b77b
--- /dev/null
+++ b/ql/test/parsing/valid/test004.ql
@@ -0,0 +1,5 @@
+// Form with question of type integer
+form testForm {
+  "Question?"
+    var: integer
+}
\ No newline at end of file
diff --git a/ql/test/parsing/valid/test005.ql b/ql/test/parsing/valid/test005.ql
new file mode 100644
index 0000000..eafc6c1
--- /dev/null
+++ b/ql/test/parsing/valid/test005.ql
@@ -0,0 +1,5 @@
+// Form with question of type money
+form testForm {
+  "Question?"
+    var: money
+}
\ No newline at end of file
diff --git a/ql/test/parsing/valid/test006.ql b/ql/test/parsing/valid/test006.ql
new file mode 100644
index 0000000..16efa4d
--- /dev/null
+++ b/ql/test/parsing/valid/test006.ql
@@ -0,0 +1,5 @@
+// Form with question of type string
+form testForm {
+  "Question?"
+    var: string
+}
\ No newline at end of file
diff --git a/ql/test/parsing/valid/test007.ql b/ql/test/parsing/valid/test007.ql
new file mode 100644
index 0000000..dd2b47a
--- /dev/null
+++ b/ql/test/parsing/valid/test007.ql
@@ -0,0 +1,8 @@
+// Form with two questions with the same identifier
+form testForm {
+  "Question?"
+    var: boolean
+
+  "Question?"
+    var: boolean
+}
diff --git a/ql/test/parsing/valid/test008.ql b/ql/test/parsing/valid/test008.ql
new file mode 100644
index 0000000..20cb866
--- /dev/null
+++ b/ql/test/parsing/valid/test008.ql
@@ -0,0 +1,8 @@
+// Form with two questions with different identifiers
+form testForm {
+  "Question?"
+    var1: boolean
+
+  "Question?"
+    var2: boolean
+}
diff --git a/ql/test/parsing/valid/test009.ql b/ql/test/parsing/valid/test009.ql
new file mode 100644
index 0000000..a4edfa1
--- /dev/null
+++ b/ql/test/parsing/valid/test009.ql
@@ -0,0 +1,20 @@
+// Form with questions of all supported types
+form testForm {
+  "Question?"
+    var1: boolean
+
+  "Question?"
+    var2: date
+
+  "Question?"
+    var3: decimal
+
+  "Question?"
+    var4: integer
+
+  "Question?"
+    var5: money
+
+  "Question?"
+    var6: string
+}
diff --git a/ql/test/parsing/valid/test010.ql b/ql/test/parsing/valid/test010.ql
new file mode 100644
index 0000000..c1985f8
--- /dev/null
+++ b/ql/test/parsing/valid/test010.ql
@@ -0,0 +1,5 @@
+// Form with computed question
+form testForm {
+  "Question?"
+    var: boolean = True
+}
\ No newline at end of file
diff --git a/ql/test/parsing/valid/test011.ql b/ql/test/parsing/valid/test011.ql
new file mode 100644
index 0000000..a59cae6
--- /dev/null
+++ b/ql/test/parsing/valid/test011.ql
@@ -0,0 +1,5 @@
+// Form with computed question
+form testForm {
+  "Question?"
+    var: boolean = False
+}
\ No newline at end of file
diff --git a/ql/test/parsing/valid/test012.ql b/ql/test/parsing/valid/test012.ql
new file mode 100644
index 0000000..d745fba
--- /dev/null
+++ b/ql/test/parsing/valid/test012.ql
@@ -0,0 +1,5 @@
+// Form with computed question
+form testForm {
+  "Question?"
+    var: boolean = "ADSADsad"
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/__pycache__/test_semantic_analysis.cpython-35.pyc b/ql/test/semantic_analysis/__pycache__/test_semantic_analysis.cpython-35.pyc
new file mode 100644
index 0000000..5b92465
--- /dev/null
+++ b/ql/test/semantic_analysis/__pycache__/test_semantic_analysis.cpython-35.pyc
diff --git a/ql/test/semantic_analysis/invalid/test001.ql b/ql/test/semantic_analysis/invalid/test001.ql
new file mode 100644
index 0000000..42b1b41
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test001.ql
@@ -0,0 +1,9 @@
+// Reference to unknown identifier in condition
+form testForm {
+	if (unknownIdentifier) {
+		"First Question"
+		anotherIdentifier : integer
+	}
+	"Second Question"
+	testIdentifier : boolean
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test002.ql b/ql/test/semantic_analysis/invalid/test002.ql
new file mode 100644
index 0000000..856447d
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test002.ql
@@ -0,0 +1,9 @@
+// Reference to unknown identifier in computed question
+form testForm {
+	"First Question"
+	testIdentifier : integer
+	"Second Question"
+	anotherIdentifier : integer = testIdentifier + unknownIdentifier
+}
+
+
diff --git a/ql/test/semantic_analysis/invalid/test003.ql b/ql/test/semantic_analysis/invalid/test003.ql
new file mode 100644
index 0000000..1491a85
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test003.ql
@@ -0,0 +1,13 @@
+// Reference to identifier in condition out of scope
+form testForm {
+	"First Question"
+	testIdentifier : boolean
+	if (testIdentifier) {
+		"Second Question"
+		anotherIdentifier : integer
+	}
+	if (anotherIdentifier) {
+		"Unreachable Question"
+		unreachableIdentifier : integer
+	}
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test004.ql b/ql/test/semantic_analysis/invalid/test004.ql
new file mode 100644
index 0000000..5ae3e94
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test004.ql
@@ -0,0 +1,11 @@
+// Reference to identifier in computed question out of scope
+form testForm {
+	"First Question"
+	testIdentifier : boolean
+	if (testIdentifier) {
+		"Second Question"
+		anotherIdentifier : integer
+	}
+	"Third Question"
+	unknownIdentifier : integer = anotherIdentifier + 1
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test005.ql b/ql/test/semantic_analysis/invalid/test005.ql
new file mode 100644
index 0000000..de066f2
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test005.ql
@@ -0,0 +1,5 @@
+// Identifier dependent on itself (reflexive)
+form testForm {
+	"First Question"
+	firstIdentifier : integer = firstIdentifier + 1
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test006.ql b/ql/test/semantic_analysis/invalid/test006.ql
new file mode 100644
index 0000000..12cf8f0
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test006.ql
@@ -0,0 +1,7 @@
+// Identifiers dependent on each other (symmetric)
+form testForm {
+	"First Question"
+	firstIdentifier : integer = secondIdentifier + 1
+	"Second Question"
+	secondIdentifier : integer = firstIdentifier + 1
+}
diff --git a/ql/test/semantic_analysis/invalid/test007.ql b/ql/test/semantic_analysis/invalid/test007.ql
new file mode 100644
index 0000000..08f4f5f
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test007.ql
@@ -0,0 +1,9 @@
+// Identifiers dependent on each other (transitive)
+form testForm {
+	"First Question"
+	firstIdentifier : integer = secondIdentifier + 1
+	"Second Question"
+	secondIdentifier : integer = thirdIdentifier + 1
+	"Third Question"
+	thirdIdentifier : integer = firstIdentifier + 1
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test008.ql b/ql/test/semantic_analysis/invalid/test008.ql
new file mode 100644
index 0000000..6c8a660
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test008.ql
@@ -0,0 +1,7 @@
+// Different questions with equal identifier
+form testForm {
+	"First Question"
+	someIdentifier : integer
+	"Second Question"
+	someIdentifier : decimal
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test009.ql b/ql/test/semantic_analysis/invalid/test009.ql
new file mode 100644
index 0000000..362a2b1
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test009.ql
@@ -0,0 +1,7 @@
+// Equal questions with different types
+form testForm {
+	"First Question"
+	someIdentifier : integer
+	"First Question"
+	someIdentifier : decimal
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test010.ql b/ql/test/semantic_analysis/invalid/test010.ql
new file mode 100644
index 0000000..30a03e2
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test010.ql
@@ -0,0 +1,5 @@
+// Incompatible types for addition operation
+form testForm {
+	"First Question"
+	someIdentifier : decimal = 10.0 + True
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test011.ql b/ql/test/semantic_analysis/invalid/test011.ql
new file mode 100644
index 0000000..de59f13
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test011.ql
@@ -0,0 +1,5 @@
+// Incompatible types for subtraction operation
+form testForm {
+	"First Question"
+	someIdentifier : decimal = 10.0 - True
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test012.ql b/ql/test/semantic_analysis/invalid/test012.ql
new file mode 100644
index 0000000..006bd0c
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test012.ql
@@ -0,0 +1,5 @@
+// Incompatible types for greater equals operation
+form testForm {
+	"First Question"
+	someIdentifier : boolean = 10.0 >= True
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test013.ql b/ql/test/semantic_analysis/invalid/test013.ql
new file mode 100644
index 0000000..2896f80
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test013.ql
@@ -0,0 +1,5 @@
+// Incompatible types for greater than operation 
+form testForm {
+	"First Question"
+	someIdentifier : boolean = 10.0 > True
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test014.ql b/ql/test/semantic_analysis/invalid/test014.ql
new file mode 100644
index 0000000..b5b7774
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test014.ql
@@ -0,0 +1,5 @@
+// Incompatible types for less equals operation
+form testForm {
+	"First Question"
+	someIdentifier : boolean = 10.0 <= True
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test015.ql b/ql/test/semantic_analysis/invalid/test015.ql
new file mode 100644
index 0000000..6c52b37
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test015.ql
@@ -0,0 +1,5 @@
+// Incompatible types for less than operation
+form testForm {
+	"First Question"
+	someIdentifier : boolean = 10.0 < True
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test016.ql b/ql/test/semantic_analysis/invalid/test016.ql
new file mode 100644
index 0000000..dcf98ea
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test016.ql
@@ -0,0 +1,5 @@
+// Incompatible types for and operation
+form testForm {
+	"First Question"
+	someIdentifier : boolean = 10.0 && True
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test017.ql b/ql/test/semantic_analysis/invalid/test017.ql
new file mode 100644
index 0000000..9eef105
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test017.ql
@@ -0,0 +1,5 @@
+// Incompatible types for or operation
+form testForm {
+	"First Question"
+	someIdentifier : boolean = 10.0 || True
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test018.ql b/ql/test/semantic_analysis/invalid/test018.ql
new file mode 100644
index 0000000..bd18cf9
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test018.ql
@@ -0,0 +1,5 @@
+// Incompatible types for multiplication operation
+form testForm {
+	"First Question"
+	someIdentifier : decimal = 10.0 * True
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test019.ql b/ql/test/semantic_analysis/invalid/test019.ql
new file mode 100644
index 0000000..69a2c38
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test019.ql
@@ -0,0 +1,5 @@
+// Incompatible types for division operation
+form testForm {
+	"First Question"
+	someIdentifier : decimal = 10.0 / True
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test020.ql b/ql/test/semantic_analysis/invalid/test020.ql
new file mode 100644
index 0000000..538bdf9
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test020.ql
@@ -0,0 +1,5 @@
+// Incompatible result type for addition operation
+form testForm {
+	"First Question"
+	someIdentifier : integer = 10.1 + 10
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test021.ql b/ql/test/semantic_analysis/invalid/test021.ql
new file mode 100644
index 0000000..74e596d
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test021.ql
@@ -0,0 +1,5 @@
+// Incompatible result type for subtraction operation
+form testForm {
+	"First Question"
+	someIdentifier : integer = 10.1 - 10
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test022.ql b/ql/test/semantic_analysis/invalid/test022.ql
new file mode 100644
index 0000000..9cf774a
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test022.ql
@@ -0,0 +1,5 @@
+// Incompatible result type for greater equals operation
+form testForm {
+	"First Question"
+	someIdentifier : integer = 10.0 >= 10
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test023.ql b/ql/test/semantic_analysis/invalid/test023.ql
new file mode 100644
index 0000000..f7d674b
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test023.ql
@@ -0,0 +1,5 @@
+// Incompatible result type for greater than operation 
+form testForm {
+	"First Question"
+	someIdentifier : integer = 10.0 > 10
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test024.ql b/ql/test/semantic_analysis/invalid/test024.ql
new file mode 100644
index 0000000..f262f5c
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test024.ql
@@ -0,0 +1,5 @@
+// Incompatible result type for less equals operation
+form testForm {
+	"First Question"
+	someIdentifier : integer = 10.0 <= 10
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test025.ql b/ql/test/semantic_analysis/invalid/test025.ql
new file mode 100644
index 0000000..ef823b5
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test025.ql
@@ -0,0 +1,5 @@
+// Incompatible result type for less than operation
+form testForm {
+	"First Question"
+	someIdentifier : integer = 10.0 < 10
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test026.ql b/ql/test/semantic_analysis/invalid/test026.ql
new file mode 100644
index 0000000..b1e8a5b
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test026.ql
@@ -0,0 +1,5 @@
+// Incompatible result type for and operation
+form testForm {
+	"First Question"
+	someIdentifier : integer = True && True
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test027.ql b/ql/test/semantic_analysis/invalid/test027.ql
new file mode 100644
index 0000000..262aa0e
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test027.ql
@@ -0,0 +1,5 @@
+// Incompatible result type for or operation
+form testForm {
+	"First Question"
+	someIdentifier : integer = False || True
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test028.ql b/ql/test/semantic_analysis/invalid/test028.ql
new file mode 100644
index 0000000..ea02ccd
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test028.ql
@@ -0,0 +1,5 @@
+// Incompatible result type for multiplication operation
+form testForm {
+	"First Question"
+	someIdentifier : integer = 10.1 * 10
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test029.ql b/ql/test/semantic_analysis/invalid/test029.ql
new file mode 100644
index 0000000..23f3c78
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test029.ql
@@ -0,0 +1,5 @@
+// Incompatible result type for division operation
+form testForm {
+	"First Question"
+	someIdentifier : integer = 10.1 / 10
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test030.ql b/ql/test/semantic_analysis/invalid/test030.ql
new file mode 100644
index 0000000..3de208c
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test030.ql
@@ -0,0 +1,7 @@
+// Complex condition with incompatible types
+form testForm {
+	if ((15.5 >= 15) && ((3.0 * True) - 15 > -10 / 2)) {
+		"First Question"
+		someIdentifier : integer
+	}
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test031.ql b/ql/test/semantic_analysis/invalid/test031.ql
new file mode 100644
index 0000000..0d6f75c
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test031.ql
@@ -0,0 +1,5 @@
+// Complex computed question with incompatible types
+form testForm {
+	"First Question"
+	someIdentifier : boolean = (25.5 >= True) && ((10.0 / 3) - 15 < -10 * 2)
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/invalid/test032.ql b/ql/test/semantic_analysis/invalid/test032.ql
new file mode 100644
index 0000000..9de5ff2
--- /dev/null
+++ b/ql/test/semantic_analysis/invalid/test032.ql
@@ -0,0 +1,5 @@
+// Complex computed question with incompatible result type
+form testForm {
+	"First Question"
+	someIdentifier : integer = (25.5 >= 10) && ((10.0 / 3) - 15 < -10 * 2)
+}
diff --git a/ql/test/semantic_analysis/test_semantic_analysis.py b/ql/test/semantic_analysis/test_semantic_analysis.py
new file mode 100644
index 0000000..ca01231
--- /dev/null
+++ b/ql/test/semantic_analysis/test_semantic_analysis.py
@@ -0,0 +1,39 @@
+from ql.ast.checkers.dependency_checker import DependencyChecker
+from ql.ast.checkers.question_checker import QuestionChecker
+from ql.ast.checkers.reference_checker import ReferenceChecker
+from ql.ast.extractors.extractor import extract_identifier_dependencies
+from ql.ast.extractors.extractor import extract_identifier_scopes
+from ql.ast.extractors.extractor import extract_identifier_types
+from ql.ast.extractors.extractor import extract_questions
+from ql.ast.visitors.type_visitor import TypeVisitor
+from ql.test.test import Test
+
+
+class TestSemanticAnalysis(Test):
+    def __init__(self, directory, lexer, parser):
+        super(TestSemanticAnalysis, self).__init__('semantic analysis', directory)
+        self.__lexer = lexer
+        self.__parser = parser
+
+    def test_file(self, file):
+        ast = self.__parser.parse(file, self.__lexer.lexer)
+
+        reference_errors = ReferenceChecker(extract_identifier_scopes(ast)).errors
+        if reference_errors:
+            return False
+
+        dependency_errors = DependencyChecker(extract_identifier_dependencies(ast)).errors
+        if dependency_errors:
+            return False
+
+        question_errors = QuestionChecker(extract_questions(ast)).errors
+        if question_errors:
+            return False
+
+        type_visitor = TypeVisitor(extract_identifier_types(ast))
+        type_visitor.visit(ast)
+        type_errors = type_visitor.errors
+        if type_errors:
+            return False
+
+        return True
diff --git a/ql/test/semantic_analysis/valid/test001.ql b/ql/test/semantic_analysis/valid/test001.ql
new file mode 100644
index 0000000..d9d037f
--- /dev/null
+++ b/ql/test/semantic_analysis/valid/test001.ql
@@ -0,0 +1,9 @@
+// Identifier reference in condition
+form testForm {
+	"First Question"
+	testIdentifier : boolean
+	if (testIdentifier) {
+		"Second Question"
+		anotherIdentifier : integer
+	}
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/valid/test002.ql b/ql/test/semantic_analysis/valid/test002.ql
new file mode 100644
index 0000000..afe1f5c
--- /dev/null
+++ b/ql/test/semantic_analysis/valid/test002.ql
@@ -0,0 +1,7 @@
+// Identifier reference in computed question
+form testForm {
+	"First Question"
+	testIdentifier : integer
+	"Second Question"
+	anotherIdentifier : integer = testIdentifier
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/valid/test003.ql b/ql/test/semantic_analysis/valid/test003.ql
new file mode 100644
index 0000000..b89d0c1
--- /dev/null
+++ b/ql/test/semantic_analysis/valid/test003.ql
@@ -0,0 +1,9 @@
+// Identifier declared after reference in condition
+form testForm {
+	if (testIdentifier) {
+		"First Question"
+		anotherIdentifier : integer
+	}
+	"Second Question"
+	testIdentifier : boolean
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/valid/test004.ql b/ql/test/semantic_analysis/valid/test004.ql
new file mode 100644
index 0000000..8f4feb0
--- /dev/null
+++ b/ql/test/semantic_analysis/valid/test004.ql
@@ -0,0 +1,7 @@
+// Identifier declared after reference in computed question
+form testForm {
+	"First Question"
+	anotherIdentifier : integer = testIdentifier + 1
+	"Second Question"
+	testIdentifier : integer
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/valid/test005.ql b/ql/test/semantic_analysis/valid/test005.ql
new file mode 100644
index 0000000..8620dc9
--- /dev/null
+++ b/ql/test/semantic_analysis/valid/test005.ql
@@ -0,0 +1,15 @@
+// Identifier reference in nested condition
+form testForm {
+	"First Question"
+	firstCondition : boolean
+	"Second Question"
+	secondCondition : boolean
+	if (firstCondition) {
+		"Third Question"
+		anotherIdentifier : integer
+		if (secondCondition) {
+			"Fourth Question"
+			yetAnotherIdentifier : decimal
+		}
+	}
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/valid/test006.ql b/ql/test/semantic_analysis/valid/test006.ql
new file mode 100644
index 0000000..855332e
--- /dev/null
+++ b/ql/test/semantic_analysis/valid/test006.ql
@@ -0,0 +1,13 @@
+// Identifier reference in nested computed question
+form testForm {
+	"First Question"
+	firstCondition : boolean
+	"Second Question"
+	firstInteger : integer
+	if (firstCondition) {
+		"Third Question"
+		anotherIdentifier : integer
+		"Fourth Question"
+		yetAnotherIdentifier : integer = firstInteger + 1
+	}
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/valid/test007.ql b/ql/test/semantic_analysis/valid/test007.ql
new file mode 100644
index 0000000..1338a82
--- /dev/null
+++ b/ql/test/semantic_analysis/valid/test007.ql
@@ -0,0 +1,9 @@
+// Identifier reference in both condition and computed question
+form testForm {
+    "First Question"
+    someInteger : integer
+    if (someInteger > 10) {
+        "Second Question"
+        computedInteger : integer = someInteger - 10
+    }
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/valid/test008.ql b/ql/test/semantic_analysis/valid/test008.ql
new file mode 100644
index 0000000..80205a5
--- /dev/null
+++ b/ql/test/semantic_analysis/valid/test008.ql
@@ -0,0 +1,9 @@
+// Identifier dependant on second, second dependant on third
+form testForm {
+	"First Question"
+	firstIdentifier : integer = secondIdentifier + 1
+	"Second Question"
+	secondIdentifier : integer = thirdIdentifier + 1
+	"Third Question"
+	thirdIdentifier : integer
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/valid/test009.ql b/ql/test/semantic_analysis/valid/test009.ql
new file mode 100644
index 0000000..7e92ad7
--- /dev/null
+++ b/ql/test/semantic_analysis/valid/test009.ql
@@ -0,0 +1,7 @@
+// Different questions with equal labels
+form testForm {
+	"First Question"
+	someIdentifier : integer
+	"First Question"
+	anotherIdentifier : decimal
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/valid/test010.ql b/ql/test/semantic_analysis/valid/test010.ql
new file mode 100644
index 0000000..eca4ad4
--- /dev/null
+++ b/ql/test/semantic_analysis/valid/test010.ql
@@ -0,0 +1,5 @@
+// Compatible types for addition operation
+form testForm {
+	"First Question"
+	someIdentifier : decimal = 10.0 + 10
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/valid/test011.ql b/ql/test/semantic_analysis/valid/test011.ql
new file mode 100644
index 0000000..f47b435
--- /dev/null
+++ b/ql/test/semantic_analysis/valid/test011.ql
@@ -0,0 +1,5 @@
+// Compatible types for subtraction operation
+form testForm {
+	"First Question"
+	someIdentifier : decimal = 10.0 - 10
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/valid/test012.ql b/ql/test/semantic_analysis/valid/test012.ql
new file mode 100644
index 0000000..2e7e278
--- /dev/null
+++ b/ql/test/semantic_analysis/valid/test012.ql
@@ -0,0 +1,5 @@
+// Compatible types for greater equals operation
+form testForm {
+	"First Question"
+	someIdentifier : boolean = 10.0 == 10
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/valid/test013.ql b/ql/test/semantic_analysis/valid/test013.ql
new file mode 100644
index 0000000..a34566c
--- /dev/null
+++ b/ql/test/semantic_analysis/valid/test013.ql
@@ -0,0 +1,5 @@
+// Compatible types for greater than operation 
+form testForm {
+	"First Question"
+	someIdentifier : boolean = 10.0 > 10
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/valid/test014.ql b/ql/test/semantic_analysis/valid/test014.ql
new file mode 100644
index 0000000..7ee1b86
--- /dev/null
+++ b/ql/test/semantic_analysis/valid/test014.ql
@@ -0,0 +1,5 @@
+// Compatible types for less equals operation
+form testForm {
+	"First Question"
+	someIdentifier : boolean = 10.0 <= 10
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/valid/test015.ql b/ql/test/semantic_analysis/valid/test015.ql
new file mode 100644
index 0000000..431c1f0
--- /dev/null
+++ b/ql/test/semantic_analysis/valid/test015.ql
@@ -0,0 +1,5 @@
+// Compatible types for less than operation
+form testForm {
+	"First Question"
+	someIdentifier : boolean = 10.0 < 10
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/valid/test016.ql b/ql/test/semantic_analysis/valid/test016.ql
new file mode 100644
index 0000000..8b0bdde
--- /dev/null
+++ b/ql/test/semantic_analysis/valid/test016.ql
@@ -0,0 +1,5 @@
+// Compatible types for and operation
+form testForm {
+	"First Question"
+	someIdentifier : boolean = True && False
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/valid/test017.ql b/ql/test/semantic_analysis/valid/test017.ql
new file mode 100644
index 0000000..851e5ff
--- /dev/null
+++ b/ql/test/semantic_analysis/valid/test017.ql
@@ -0,0 +1,5 @@
+// Compatible types for or operation
+form testForm {
+	"First Question"
+	someIdentifier : boolean = False || True
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/valid/test018.ql b/ql/test/semantic_analysis/valid/test018.ql
new file mode 100644
index 0000000..41d439f
--- /dev/null
+++ b/ql/test/semantic_analysis/valid/test018.ql
@@ -0,0 +1,5 @@
+// Compatible types for multiplication operation
+form testForm {
+	"First Question"
+	someIdentifier : decimal = 10.0 * 10
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/valid/test019.ql b/ql/test/semantic_analysis/valid/test019.ql
new file mode 100644
index 0000000..36ba458
--- /dev/null
+++ b/ql/test/semantic_analysis/valid/test019.ql
@@ -0,0 +1,5 @@
+// Compatible types for division operation
+form testForm {
+	"First Question"
+	someIdentifier : decimal = 10.0 / 10
+}
diff --git a/ql/test/semantic_analysis/valid/test020.ql b/ql/test/semantic_analysis/valid/test020.ql
new file mode 100644
index 0000000..9fff193
--- /dev/null
+++ b/ql/test/semantic_analysis/valid/test020.ql
@@ -0,0 +1,7 @@
+// Complex condition with mixed types
+form testForm {
+	if ((15.5 >= 15) && ((3.0 * 3) - 15 > -10 / 2)) {
+		"First Question"
+		someIdentifier : integer
+	}
+}
\ No newline at end of file
diff --git a/ql/test/semantic_analysis/valid/test021.ql b/ql/test/semantic_analysis/valid/test021.ql
new file mode 100644
index 0000000..01ec35c
--- /dev/null
+++ b/ql/test/semantic_analysis/valid/test021.ql
@@ -0,0 +1,5 @@
+// Complex computed question with mixed types
+form testForm {
+	"First Question"
+	someIdentifier : boolean = (25.5 >= 10) && ((10.0 / 3) - 15 < -10 * 2)
+}
\ No newline at end of file
diff --git a/ql/test/test.py b/ql/test/test.py
new file mode 100644
index 0000000..79b67d4
--- /dev/null
+++ b/ql/test/test.py
@@ -0,0 +1,80 @@
+from os import listdir
+from os import path
+
+from termcolor import colored
+
+
+class Test:
+    def __init__(self, name, directory):
+        self.__name = name
+        self.directory = directory
+        self.valid_files = self.get_directory_files(directory + 'valid')
+        self.invalid_files = self.get_directory_files(directory + 'invalid')
+
+    @property
+    def name(self):
+        return self.__name
+
+    @staticmethod
+    def get_directory_files(directory):
+        if path.exists(directory):
+            return sorted(listdir(directory))
+
+        return []
+
+    def test(self):
+        successes = 0
+        print('-------------------------------------------------------------------------------------------\n')
+        print('Performing {} tests.\n'.format(self.name))
+        print('-------------------------------------------------------------------------------------------\n')
+
+        if self.valid_files:
+            print('Performing valid tests:')
+            successes += self.test_valid_files()
+            print()
+
+        if self.invalid_files:
+            print('Performing invalid tests:')
+            successes += self.test_invalid_files()
+            print()
+
+        print('{} out of {} {} tests successful.\n'.format(successes, len(self.valid_files) + len(self.invalid_files),
+                                                           self.name))
+
+    def test_file(self, file):
+        pass
+
+    def test_valid_files(self, valid=True):
+        successes = 0
+
+        for file in self.valid_files:
+            test = open(self.directory + 'valid/' + file, 'r').read()
+            result = valid == self.test_file(test)
+            self.print_result(file, result, test.split('\n')[0])
+
+            if result:
+                successes += 1
+
+        return successes
+
+    def test_invalid_files(self, valid=False):
+        successes = 0
+
+        for file in self.invalid_files:
+            test = open(self.directory + 'invalid/' + file, 'r').read()
+            result = valid == self.test_file(test)
+            self.print_result(file, result, test.split('\n')[0])
+
+            if result:
+                successes += 1
+
+        return successes
+
+    @staticmethod
+    def print_result(file, result=True, test=''):
+        tag = colored('[failure]', 'red')
+
+        if result:
+            tag = colored('[success]', 'green')
+
+        print(tag, file, test.strip('//').strip())
diff --git a/ql/types/__pycache__/boolean.cpython-35.pyc b/ql/types/__pycache__/boolean.cpython-35.pyc
new file mode 100644
index 0000000..0acd5ee
--- /dev/null
+++ b/ql/types/__pycache__/boolean.cpython-35.pyc
diff --git a/ql/types/__pycache__/date.cpython-35.pyc b/ql/types/__pycache__/date.cpython-35.pyc
new file mode 100644
index 0000000..389ffc4
--- /dev/null
+++ b/ql/types/__pycache__/date.cpython-35.pyc
diff --git a/ql/types/__pycache__/decimal.cpython-35.pyc b/ql/types/__pycache__/decimal.cpython-35.pyc
new file mode 100644
index 0000000..03e70c2
--- /dev/null
+++ b/ql/types/__pycache__/decimal.cpython-35.pyc
diff --git a/ql/types/__pycache__/integer.cpython-35.pyc b/ql/types/__pycache__/integer.cpython-35.pyc
new file mode 100644
index 0000000..eacf953
--- /dev/null
+++ b/ql/types/__pycache__/integer.cpython-35.pyc
diff --git a/ql/types/__pycache__/money.cpython-35.pyc b/ql/types/__pycache__/money.cpython-35.pyc
new file mode 100644
index 0000000..4213628
--- /dev/null
+++ b/ql/types/__pycache__/money.cpython-35.pyc
diff --git a/ql/types/__pycache__/string.cpython-35.pyc b/ql/types/__pycache__/string.cpython-35.pyc
new file mode 100644
index 0000000..18b2f54
--- /dev/null
+++ b/ql/types/__pycache__/string.cpython-35.pyc
diff --git a/ql/types/__pycache__/type.cpython-35.pyc b/ql/types/__pycache__/type.cpython-35.pyc
new file mode 100644
index 0000000..f81c2f7
--- /dev/null
+++ b/ql/types/__pycache__/type.cpython-35.pyc
diff --git a/ql/types/__pycache__/undefined.cpython-35.pyc b/ql/types/__pycache__/undefined.cpython-35.pyc
new file mode 100644
index 0000000..ddc6cc1
--- /dev/null
+++ b/ql/types/__pycache__/undefined.cpython-35.pyc
diff --git a/ql/types/boolean.py b/ql/types/boolean.py
new file mode 100644
index 0000000..f9dc76c
--- /dev/null
+++ b/ql/types/boolean.py
@@ -0,0 +1,42 @@
+from gui.widgets.checkbox import CheckBox
+from ql.ast.nodes.expressions.literals.boolean_literal import BooleanNode
+from ql.types.type import QLType
+
+
+class QLBoolean(QLType):
+    def __init__(self, value=False):
+        super(QLBoolean, self).__init__()
+        self.__value = bool(value)
+
+    @property
+    def value(self):
+        return self.__value
+
+    def __bool__(self):
+        return bool(self.value)
+
+    def __str__(self):
+        return str(self.value)
+
+    def __repr__(self):
+        return str(self.value)
+
+    def __eq__(self, other):
+        if isinstance(other, QLBoolean):
+            return QLBoolean(self.value == other.value)
+
+        return QLBoolean(False)
+
+    def __ne__(self, other):
+        return QLBoolean(not self == other)
+
+    def get_json_value(self):
+        return self.value
+
+    @staticmethod
+    def get_literal_node(value):
+        return BooleanNode(None, QLBoolean, value)
+
+    @staticmethod
+    def pyqt5_default_widget():
+        return CheckBox()
diff --git a/ql/types/date.py b/ql/types/date.py
new file mode 100644
index 0000000..fca5366
--- /dev/null
+++ b/ql/types/date.py
@@ -0,0 +1,67 @@
+from datetime import date
+
+from gui.widgets.calendar import CalendarWidget
+from ql.ast.nodes.expressions.literals.date_literal import DateNode
+from ql.types.boolean import QLBoolean
+from ql.types.type import QLType
+
+
+class QLDate(QLType):
+    def __init__(self, day=1, month=1, year=1):
+        super(QLDate, self).__init__()
+        self.__day = int(day)
+        self.__month = int(month)
+        self.__year = int(year)
+        date(self.year, self.month, self.day)
+
+    @property
+    def day(self):
+        return self.__day
+
+    @property
+    def month(self):
+        return self.__month
+
+    @property
+    def year(self):
+        return self.__year
+
+    def __repr__(self):
+        return '{}-{}-{}'.format(self.day, self.month, self.year)
+
+    def __str__(self):
+        return '{}-{}-{}'.format(self.day, self.month, self.year)
+
+    def __eq__(self, other):
+        if isinstance(other, QLDate):
+            return QLBoolean(self.day == other.day and self.month == other.month and self.year == other.year)
+
+        return QLBoolean(False)
+
+    def __ne__(self, other):
+        return QLBoolean(not self == other)
+
+    def __lt__(self, other):
+        return QLBoolean(self.year < other.year or (self.month < other.month and self.year == other.year) or
+                         (self.day < other.day and self.month == other.month and self.year == other.year))
+
+    def __gt__(self, other):
+        return QLBoolean(self.year > other.year or (self.month > other.month and self.year == other.year) or
+                         (self.day > other.day and self.month == other.month and self.year == other.year))
+
+    def __le__(self, other):
+        return QLBoolean(self < other or self == other)
+
+    def __ge__(self, other):
+        return QLBoolean(self > other or self == other)
+
+    def get_json_value(self):
+        return {'day': self.day, 'month': self.month, 'year': self.year}
+
+    @staticmethod
+    def get_literal_node(value):
+        return DateNode(None, QLDate, value)
+
+    @staticmethod
+    def pyqt5_default_widget():
+        return CalendarWidget()
diff --git a/ql/types/decimal.py b/ql/types/decimal.py
new file mode 100644
index 0000000..af0952d
--- /dev/null
+++ b/ql/types/decimal.py
@@ -0,0 +1,74 @@
+from gui.widgets.double_spinbox import DoubleSpinBox
+from ql.ast.nodes.expressions.literals.decimal_literal import DecimalNode
+from ql.types.boolean import QLBoolean
+from ql.types.money import QLMoney
+from ql.types.type import QLType
+
+
+class QLDecimal(QLType):
+    def __init__(self, value=0.0):
+        super(QLDecimal, self).__init__()
+        self.__value = float(value)
+
+    @property
+    def value(self):
+        return self.__value
+
+    def __repr__(self):
+        return str(self.value)
+
+    def __str__(self):
+        return str(self.value)
+
+    def __neg__(self):
+        return QLDecimal(- self.value)
+
+    def __eq__(self, other):
+        if isinstance(other, QLDecimal):
+            return QLBoolean(self.value == other.value)
+
+        return QLBoolean(False)
+
+    def __ne__(self, other):
+        return QLBoolean(not self == other)
+
+    def __lt__(self, other):
+        return QLBoolean(self.value < other.value)
+
+    def __gt__(self, other):
+        return QLBoolean(self.value > other.value)
+
+    def __le__(self, other):
+        return QLBoolean(self.value <= other.value)
+
+    def __ge__(self, other):
+        return QLBoolean(self.value >= other.value)
+
+    def __add__(self, other):
+        return QLDecimal(self.value + other.value)
+
+    def __sub__(self, other):
+        return QLDecimal(self.value - other.value)
+
+    def __mul__(self, other):
+        if isinstance(other, QLMoney):
+            return QLMoney(self.value * other.value, other.currency)
+
+        return QLDecimal(self.value * other.value)
+
+    def __truediv__(self, other):
+        if isinstance(other, QLMoney):
+            return QLMoney(other.value / self.value, other.currency)
+
+        return QLDecimal(self.value / other.value)
+
+    def get_json_value(self):
+        return self.value
+
+    @staticmethod
+    def get_literal_node(value):
+        return DecimalNode(None, QLDecimal, value)
+
+    @staticmethod
+    def pyqt5_default_widget():
+        return DoubleSpinBox()
diff --git a/ql/types/integer.py b/ql/types/integer.py
new file mode 100644
index 0000000..ddc8666
--- /dev/null
+++ b/ql/types/integer.py
@@ -0,0 +1,75 @@
+from gui.widgets.spinbox import SpinBox
+from ql.ast.nodes.expressions.literals.integer_literal import IntegerNode
+from ql.types.boolean import QLBoolean
+from ql.types.decimal import QLDecimal
+from ql.types.money import QLMoney
+from ql.types.type import QLType
+
+
+class QLInteger(QLType):
+    def __init__(self, value=0):
+        super(QLInteger, self).__init__()
+        self.__value = int(value)
+
+    @property
+    def value(self):
+        return self.__value
+
+    def __repr__(self):
+        return str(self.value)
+
+    def __str__(self):
+        return str(self.value)
+
+    def __neg__(self):
+        return QLInteger(- self.value)
+
+    def __eq__(self, other):
+        if isinstance(other, QLInteger):
+            return QLBoolean(self.value == other.value)
+
+        return QLBoolean(False)
+
+    def __ne__(self, other):
+        return QLBoolean(not self == other)
+
+    def __lt__(self, other):
+        return QLBoolean(self.value < other.value)
+
+    def __gt__(self, other):
+        return QLBoolean(self.value > other.value)
+
+    def __le__(self, other):
+        return QLBoolean(self.value <= other.value)
+
+    def __ge__(self, other):
+        return QLBoolean(self.value >= other.value)
+
+    def __add__(self, other):
+        return type(other)(self.value + other.value)
+
+    def __sub__(self, other):
+        return type(other)(self.value - other.value)
+
+    def __mul__(self, other):
+        if isinstance(other, QLMoney):
+            return QLMoney(self.value * other.value, other.currency)
+
+        return type(other)(self.value * other.value)
+
+    def __truediv__(self, other):
+        if isinstance(other, QLMoney):
+            return QLMoney(other.value / self.value, other.currency)
+
+        return QLDecimal(self.value / other.value)
+
+    def get_json_value(self):
+        return self.value
+
+    @staticmethod
+    def get_literal_node(value):
+        return IntegerNode(None, QLInteger, value)
+
+    @staticmethod
+    def pyqt5_default_widget():
+        return SpinBox()
diff --git a/ql/types/money.py b/ql/types/money.py
new file mode 100644
index 0000000..edac58f
--- /dev/null
+++ b/ql/types/money.py
@@ -0,0 +1,76 @@
+from gui.widgets.money_spinbox import MoneySpinbox
+from ql.ast.nodes.expressions.literals.money_literal import MoneyNode
+from ql.types.boolean import QLBoolean
+from ql.types.type import QLType
+
+
+class QLMoney(QLType):
+    def __init__(self, value=0.0, currency='$'):
+        super(QLMoney, self).__init__()
+        self.__value = float(value)
+        self.__currency = currency
+
+    @property
+    def value(self):
+        return self.__value
+
+    @property
+    def currency(self):
+        return self.__currency
+
+    def __repr__(self):
+        return '{}{:.2f}'.format(self.currency, self.value)
+
+    def __str__(self):
+        return '{}{:.2f}'.format(self.currency, self.value)
+
+    def __neg__(self):
+        return QLMoney(- self.value, self.currency)
+
+    def __eq__(self, other):
+        if isinstance(other, QLMoney):
+            return QLBoolean(self.value == other.value and self.currency == other.currency)
+
+        return QLBoolean(False)
+
+    def __ne__(self, other):
+        return QLBoolean(not self == other)
+
+    def __lt__(self, other):
+        return QLBoolean(self.value < other.value and self.currency == other.currency)
+
+    def __gt__(self, other):
+        return QLBoolean(self.value > other.value and self.currency == other.currency)
+
+    def __le__(self, other):
+        return QLBoolean(self.value <= other.value and self.currency == other.currency)
+
+    def __ge__(self, other):
+        return QLBoolean(self.value >= other.value and self.currency == other.currency)
+
+    def __add__(self, other):
+        if self.currency == other.currency:
+            return QLMoney(self.value + other.value, self.currency)
+        return NotImplemented
+
+    def __sub__(self, other):
+        if self.currency == other.currency:
+            return QLMoney(self.value - other.value, self.currency)
+        return NotImplemented
+
+    def __mul__(self, other):
+        return other * self
+
+    def __truediv__(self, other):
+        return other / self
+
+    def get_json_value(self):
+        return {'value': round(self.value, 2), 'currency': self.currency}
+
+    @staticmethod
+    def get_literal_node(value):
+        return MoneyNode(None, QLMoney, value)
+
+    @staticmethod
+    def pyqt5_default_widget():
+        return MoneySpinbox()
diff --git a/ql/types/string.py b/ql/types/string.py
new file mode 100644
index 0000000..ece46a7
--- /dev/null
+++ b/ql/types/string.py
@@ -0,0 +1,55 @@
+from gui.widgets.line_edit import LineEdit
+from ql.ast.nodes.expressions.literals.string_literal import StringNode
+from ql.types.boolean import QLBoolean
+from ql.types.type import QLType
+
+
+class QLString(QLType):
+    def __init__(self, value=''):
+        super(QLString, self).__init__()
+        self.__value = str(value)
+
+    @property
+    def value(self):
+        return self.__value
+
+    def __repr__(self):
+        return str(self.value)
+
+    def __str__(self):
+        return str(self.value)
+
+    def __eq__(self, other):
+        if isinstance(other, QLString):
+            return QLBoolean(self.value == other.value)
+
+        return QLBoolean(False)
+
+    def __ne__(self, other):
+        return QLBoolean(not self == other)
+
+    def __lt__(self, other):
+        return QLBoolean(len(self.value) < len(other.value))
+
+    def __gt__(self, other):
+        return QLBoolean(len(self.value) > len(other.value))
+
+    def __le__(self, other):
+        return QLBoolean(len(self.value) <= len(other.value))
+
+    def __ge__(self, other):
+        return QLBoolean(len(self.value) >= len(other.value))
+
+    def __add__(self, other):
+        return QLString(self.value + other.value)
+
+    def get_json_value(self):
+        return self.value
+
+    @staticmethod
+    def get_literal_node(value):
+        return StringNode(None, QLString, value)
+
+    @staticmethod
+    def pyqt5_default_widget():
+        return LineEdit()
diff --git a/ql/types/type.py b/ql/types/type.py
new file mode 100644
index 0000000..912946d
--- /dev/null
+++ b/ql/types/type.py
@@ -0,0 +1,3 @@
+class QLType:
+    def __init__(self):
+        pass
diff --git a/ql/types/undefined.py b/ql/types/undefined.py
new file mode 100644
index 0000000..2deafe0
--- /dev/null
+++ b/ql/types/undefined.py
@@ -0,0 +1,40 @@
+from gui.widgets.label import Label
+from ql.ast.nodes.expressions.literals.undefined_literal import UndefinedNode
+from ql.types.boolean import QLBoolean
+from ql.types.type import QLType
+
+
+class QLUndefined(QLType):
+    def __init__(self, *unused):
+        super(QLUndefined, self).__init__()
+        self.__value = None
+
+    @property
+    def value(self):
+        return self.__value
+
+    def __bool__(self):
+        return False
+
+    def __repr__(self):
+        return 'Undefined'
+
+    def __eq__(self, other):
+        if isinstance(other, QLUndefined):
+            return QLBoolean(self.value == other.value)
+
+        return QLBoolean(False)
+
+    def __ne__(self, other):
+        return QLBoolean(not self == other)
+
+    def get_json_value(self):
+        return self.value
+
+    @staticmethod
+    def get_literal_node(unused):
+        return UndefinedNode(None, QLUndefined, QLUndefined(None))
+
+    @staticmethod
+    def pyqt5_default_widget():
+        return Label('Undefined')
diff --git a/qls/parser/lexer.py b/qls/parser/lexer.py
new file mode 100644
index 0000000..f7b8b98
--- /dev/null
+++ b/qls/parser/lexer.py
@@ -0,0 +1,117 @@
+from ply.lex import lex

+

+

+class QLSLexer:

+    def __init__(self):

+        self.__errors = []

+        self.__lexer = None

+

+    @property

+    def lexer(self):

+        return self.__lexer

+

+    @property

+    def errors(self):

+        return self.__errors

+

+    def build(self):

+        self.__lexer = lex(module=self)

+

+    def tokenize(self, data):

+        self.__errors = []

+        self.lexer.input(data)

+        token = self.lexer.token()

+        tokens = [token]

+

+        while token:

+            token = self.lexer.token()

+            tokens.append(token)

+

+        return tokens

+

+    tokens = [

+        'COLON', 'COMMA',

+        'LEFT_BRACE', 'RIGHT_BRACE',

+        'LEFT_BRACKET', 'RIGHT_BRACKET',

+        'IDENTIFIER',

+        'HEX_COLOR',

+        'INTEGER_LITERAL', 'STRING_LITERAL',

+    ]

+

+    # List of reserved keywords

+    reserved = {

+        'stylesheet':   'STYLESHEET',

+        'page':         'PAGE',

+        'section':      'SECTION',

+        'question':     'QUESTION',

+        'default':      'DEFAULT',

+

+        # Properties

+        'height':       'HEIGHT',

+        'width':        'WIDTH',

+        'font':         'FONT',

+        'fontsize':     'FONT_SIZE',

+        'color':        'COLOR',

+        'widget':       'WIDGET',

+

+        # QL types

+        'boolean':      'BOOLEAN',

+        'date':         'DATE',

+        'decimal':      'DECIMAL',

+        'integer':      'INTEGER',

+        'money':        'MONEY',

+        'string':       'STRING',

+

+        # Widgets

+        'calendar':     'CALENDAR',

+        'checkbox':     'CHECKBOX',

+        'line_edit':    'LINE_EDIT',

+        'spinbox':      'SPINBOX',

+        'radio':        'RADIO',

+    }

+

+    tokens += list(reserved.values())

+

+    # Regular expression rules for simple tokens

+    t_ignore = ' \t'

+

+    t_COLON = r':'

+    t_COMMA = r','

+

+    t_LEFT_BRACE = r'\{'

+    t_RIGHT_BRACE = r'\}'

+

+    t_LEFT_BRACKET = r'\('

+    t_RIGHT_BRACKET = r'\)'

+

+    t_HEX_COLOR = r'\#([A-Fa-f0-9]{6}|[A-Fa-f0-9]{3})'

+

+    @staticmethod

+    def t_newline(token):

+        r'\n+'

+        token.lexer.lineno += len(token.value)

+

+    @staticmethod

+    def t_eof(token):

+        token.lexer.lineno = 1

+

+    @staticmethod

+    def t_INTEGER_LITERAL(token):

+        r'\d+'

+        token.value = int(token.value)

+        return token

+

+    @staticmethod

+    def t_STRING_LITERAL(token):

+        r'\"(.+?)\"'

+        token.value = token.value[1:-1]

+        return token

+

+    def t_IDENTIFIER(self, token):

+        r'[a-zA-Z][a-zA-Z_0-9]*'

+        token.type = self.reserved.get(token.value, 'IDENTIFIER')  # Check for reserved words

+        return token

+

+    def t_error(self, token):

+        self.errors.append("Illegal character '%s'" % token.value[0])

+        token.lexer.skip(1)

diff --git a/qls/parser/parser.py b/qls/parser/parser.py
new file mode 100644
index 0000000..1637e6d
--- /dev/null
+++ b/qls/parser/parser.py
@@ -0,0 +1,215 @@
+from ply.yacc import yacc
+
+from qls.parser.lexer import QLSLexer
+
+
+class QLSParser:
+    def __init__(self):
+        self.__errors = []
+        self.__tokens = QLSLexer.tokens
+        self.__parser = None
+
+    @property
+    def errors(self):
+        return self.__errors
+
+    @property
+    def tokens(self):
+        return self.__tokens
+
+    @property
+    def parser(self):
+        return self.__parser
+
+    def build(self):
+        self.__parser = yacc(module=self)
+
+    def parse(self, data, lexer):
+        return self.parser.parse(data, lexer)
+
+    @staticmethod
+    def p_stylesheet(production):
+        """stylesheet : STYLESHEET IDENTIFIER LEFT_BRACE pages RIGHT_BRACE"""
+        production[0] = ('STYLESHEET', production[2], production[4])
+
+    # Statements
+    @staticmethod
+    def p_pages(production):
+        """pages    : page pages
+                    | page"""
+        if len(production) == 3:
+            production[0] = [production[1]] + production[2]
+        elif len(production) == 2:
+            production[0] = [production[1]]
+
+    @staticmethod
+    def p_page(production):
+        """page : PAGE IDENTIFIER LEFT_BRACE sections RIGHT_BRACE
+                | PAGE IDENTIFIER LEFT_BRACE sections default RIGHT_BRACE
+                | PAGE IDENTIFIER LEFT_BRACE default RIGHT_BRACE"""
+        if len(production) == 6:
+            production[0] = ('PAGE', production[2], production[4])
+        elif len(production) == 7:
+            production[0] = ('PAGE', production[2], production[4], production[5])
+
+    @staticmethod
+    def p_sections(production):
+        """sections : section sections
+                    | section"""
+        if len(production) == 3:
+            production[0] = [production[1]] + production[2]
+        elif len(production) == 2:
+            production[0] = [production[1]]
+
+    @staticmethod
+    def p_statement(production):
+        """statement    : section
+                        | question"""
+        production[0] = production[1]
+
+    @staticmethod
+    def p_statements(production):
+        """statements   : statement statements
+                        | statement"""
+        if len(production) == 3:
+            production[0] = [production[1]] + production[2]
+        elif len(production) == 2:
+            production[0] = [production[1]]
+
+    @staticmethod
+    def p_section(production):
+        """section  : SECTION STRING_LITERAL LEFT_BRACE statements RIGHT_BRACE
+                    | SECTION STRING_LITERAL LEFT_BRACE statements default RIGHT_BRACE
+                    | SECTION STRING_LITERAL question
+                    | SECTION STRING_LITERAL default"""
+        if len(production) == 4:
+            production[0] = ('SECTION', production[2], [production[3]])
+        elif len(production) == 6:
+            production[0] = ('SECTION', production[2], production[4])
+        elif len(production) == 7:
+            production[0] = ('SECTION', production[2], production[4], production[5])
+
+    @staticmethod
+    def p_question(production):
+        """question : QUESTION IDENTIFIER"""
+        production[0] = ('QUESTION', production[2])
+
+    @staticmethod
+    def p_question_properties(production):
+        """question : QUESTION IDENTIFIER WIDGET widget"""
+        production[0] = ('QUESTION', production[2], production[4])
+
+    @staticmethod
+    def p_default(production):
+        """default : DEFAULT type LEFT_BRACE properties RIGHT_BRACE"""
+        production[0] = ('DEFAULT', production[2], production[4])
+
+    @staticmethod
+    def p_default_widget(production):
+        """default : DEFAULT type WIDGET widget"""
+        production[0] = ('DEFAULT', production[2], production[3])
+
+    # Properties
+    @staticmethod
+    def p_properties(production):
+        """properties   : property properties
+                        | property"""
+        if len(production) == 3:
+            production[0] = [production[1]] + production[2]
+        elif len(production) == 2:
+            production[0] = [production[1]]
+
+    @staticmethod
+    def p_height(production):
+        """property : HEIGHT COLON INTEGER_LITERAL"""
+        production[0] = ('HEIGHT', production[3])
+
+    @staticmethod
+    def p_width(production):
+        """property : WIDTH COLON INTEGER_LITERAL"""
+        production[0] = ('WIDTH', production[3])
+
+    @staticmethod
+    def p_font(production):
+        """property : FONT COLON STRING_LITERAL"""
+        production[0] = ('FONT', production[3])
+
+    @staticmethod
+    def p_font_size(production):
+        """property : FONT_SIZE COLON INTEGER_LITERAL"""
+        production[0] = ('FONT_SIZE', production[3])
+
+    @staticmethod
+    def p_color(production):
+        """property : COLOR COLON HEX_COLOR"""
+        production[0] = ('COLOR', production[3])
+
+    @staticmethod
+    def p_widget(production):
+        """property : WIDGET widget"""
+        production[0] = ('WIDGET', production[2])
+
+    # Widgets
+    @staticmethod
+    def p_calendar(production):
+        """widget : CALENDAR"""
+        production[0] = 'CALENDAR'
+
+    @staticmethod
+    def p_checkbox(production):
+        """widget : CHECKBOX"""
+        production[0] = 'CHECKBOX'
+
+    @staticmethod
+    def p_line_edit(production):
+        """widget : LINE_EDIT"""
+        production[0] = 'LINE_EDIT'
+
+    @staticmethod
+    def p_spinbox(production):
+        """widget : SPINBOX"""
+        production[0] = 'SPINBOX'
+
+    @staticmethod
+    def p_radio_default(production):
+        """widget : RADIO"""
+        production[0] = 'RADIO'
+
+    @staticmethod
+    def p_radio(production):
+        """widget : RADIO LEFT_BRACKET STRING_LITERAL COMMA STRING_LITERAL RIGHT_BRACKET"""
+        production[0] = ('RADIO', production[3], production[5])
+
+    # Types
+    @staticmethod
+    def p_boolean(production):
+        """type : BOOLEAN"""
+        production[0] = 'BOOLEAN'
+
+    @staticmethod
+    def p_decimal(production):
+        """type : DECIMAL"""
+        production[0] = 'DECIMAL'
+
+    @staticmethod
+    def p_string(production):
+        """type : STRING"""
+        production[0] = 'STRING'
+
+    @staticmethod
+    def p_date(production):
+        """type : DATE"""
+        production[0] = 'DATE'
+
+    @staticmethod
+    def p_money(production):
+        """type : MONEY"""
+        production[0] = 'MONEY'
+
+    @staticmethod
+    def p_integer(production):
+        """type : INTEGER"""
+        production[0] = 'INTEGER'
+
+    def p_error(self, production):
+        self.errors.append('Syntax error at line {}, token={}'.format(production.lineno, production.type))