Fixed #18 : Parsing and evaluating Python

src/evaluators/PythonEvaluator.py

@@ -0,0 +1,31 @@
+from core.BuiltinConcepts import BuiltinConcepts
+from core.ExecutionContext import ExecutionContext, ContextActions
+from core.ReturnValue import ReturnValue
+from core.error import ErrorContext
+from evaluators.base_evaluator import EvaluatorEvalResult, EvaluatorMatchResult, OneReturnValueEvaluator
+
+
+class PythonEvaluator(OneReturnValueEvaluator):
+    NAME = "PythonEvaluator"
+
+    def __init__(self):
+        super().__init__(self.NAME, ContextActions.EVALUATION, 50)
+
+    def matches(self, context: ExecutionContext, return_value: ReturnValue) -> EvaluatorMatchResult:
+        return EvaluatorMatchResult(return_value.status and
+                                    context.sheerka.isinstance(return_value.value, BuiltinConcepts.PYTHON_CODE))
+
+    def eval(self, context: ExecutionContext,
+             evaluation_context: object,
+             return_value: ReturnValue) -> EvaluatorEvalResult:
+
+        sheerka = context.sheerka
+        fragment = return_value.value.pf
+
+        evaluated = sheerka.evaluate_python(context, fragment)
+        if isinstance(evaluated, ErrorContext):
+            return EvaluatorEvalResult([ReturnValue(self.name, False, evaluated, parents=[return_value])],
+                                       [])
+        else:
+            return EvaluatorEvalResult([ReturnValue(self.name, True, evaluated, parents=[return_value])],
+                                       [return_value])