1 files changed, 20 insertions, 0 deletions
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)