Create evaluator for not operator

smnp/runtime/evaluators/negation.py

@@ -0,0 +1,16 @@
+from smnp.error.runtime import RuntimeException
+from smnp.runtime.evaluator import Evaluator
+from smnp.runtime.evaluators.expression import expressionEvaluator
+from smnp.type.model import Type
+
+
+class NotEvaluator(Evaluator):
+
+    @classmethod
+    def evaluator(cls, node, environment):
+        value = expressionEvaluator(doAssert=True)(node.value, environment).value
+
+        if value.type != Type.BOOL:
+            raise RuntimeException(f"Operator '{node.operator.value}' is supported only by {Type.BOOL.name.lower()} type", node.pos)
+
+        return Type.bool(not value.value)