Add call stack to fix 'return' statement issue

smnp/environment/environment.py

@@ -11,6 +11,7 @@ class Environment():
         self.methods = methods
         self.customFunctions = []
         self.customMethods = []
+        self.callStack = []
 
     def invokeMethod(self, object, name, args):
         builtinMethodResult = self._invokeBuiltinMethod(object, name, args)
@@ -26,7 +27,9 @@ class Environment():
     def _invokeBuiltinMethod(self, object, name, args):
         for method in self.methods:
             if method.name == name:
+                self.callStack.append(CallStackItem(name))
                 ret = method.call(self, [object, *args])
+                self.callStack.pop(-1)
                 if ret is not None:
                     return (True, ret)
 
@@ -39,7 +42,9 @@ class Environment():
                 if signatureCheckresult[0]:
                     self.scopes.append({argName: argValue for argName, argValue in zip(method.arguments, list(signatureCheckresult[1:]))})
                     self.scopes[-1][method.alias] = object
+                    self.callStack.append(CallStackItem(name))
                     result = BodyEvaluator.evaluate(method.body, self).value  # TODO check if it isn't necessary to verify 'result' attr of EvaluatioNResult
+                    self.callStack.pop(-1)
                     self.scopes.pop(-1)
                     return (True, result)
                 raise IllegalFunctionInvocationException(f"{method.name}{method.signature.string}",
@@ -60,7 +65,9 @@ class Environment():
     def _invokeBuiltinFunction(self, name, args):
         for function in self.functions:
             if function.name == name:
+                self.callStack.append(CallStackItem(name))
                 ret = function.call(self, args)
+                self.callStack.pop(-1)
                 if ret is not None:
                     return (True, ret)
 
@@ -72,7 +79,9 @@ class Environment():
                 signatureCheckresult = function.signature.check(args)
                 if signatureCheckresult[0]:
                     self.scopes.append({ argName: argValue for argName, argValue in zip(function.arguments, list(signatureCheckresult[1:])) })
+                    self.callStack.append(CallStackItem(name))
                     result = BodyEvaluator.evaluate(function.body, self).value #TODO check if it isn't necessary to verify 'result' attr of EvaluatioNResult
+                    self.callStack.pop(-1)
                     self.scopes.pop(-1)
                     return (True, result)
                 raise IllegalFunctionInvocationException(f"{function.name}{function.signature.string}", f"{name}{types(args)}")
@@ -138,6 +147,9 @@ class Environment():
     def customMethodsToString(self):
         return "Custom Methods:\n" + ("\n".join([ f"  {function.name}(...)" for function in self.customMethods ]))
 
+    def callStackToString(self):
+        return "Call Stack:\n" + ("\n".join([ f"  [{i}]: {function.function}(...)" for i, function in reversed(list(enumerate(self.callStack))) ]))
+
     def extend(self, environment):
         self.scopes[0].update(environment.scopes[0])
         self.customFunctions.extend(environment.customFunctions)
@@ -145,12 +157,18 @@ class Environment():
 
 
     def __str__(self):
-        return f"{self.scopesToString()}\n{self.functionsToString()}\n{self.methodsToString()}\n{self.customFunctionsToString()}\n{self.customMethodsToString()}"
+        return f"{self.scopesToString()}\n{self.functionsToString()}\n{self.methodsToString()}\n{self.customFunctionsToString()}\n{self.customMethodsToString()}\n{self.callStackToString()}"
 
     def __repr__(self):
         return self.__str__()
 
 
+class CallStackItem:
+    def __init__(self, function):
+        self.function = function
+        self.value = None
+
+
 class CustomFunction:
     def __init__(self, name, signature, arguments, body):
         self.name = name

smnp/error/runtime.py

@@ -2,8 +2,9 @@ from smnp.error.base import SmnpException
 
 
 class RuntimeException(SmnpException):
-    def __init__(self, msg, pos):
+    def __init__(self, msg, pos, environment=None):
         super().__init__(msg, pos)
+        self.environment = environment
 
     def _title(self):
         return "Runtime Error"

smnp/module/system/function/debug.py

@@ -18,6 +18,9 @@ def _function(env, parameter):
     elif parameter.value == "methods":
         print(env.methodsToString())
         return
+    elif parameter.value == "callstack":
+        print(env.callStackToString())
+        return
 
     raise IllegalArgumentException(f"Unknown parameter '{parameter.value}'")
 

smnp/runtime/evaluator.py

@@ -3,6 +3,7 @@ from smnp.ast.node.extend import ExtendNode
 from smnp.ast.node.function import FunctionDefinitionNode
 from smnp.ast.node.imports import ImportNode
 from smnp.ast.node.program import Program
+from smnp.ast.node.ret import ReturnNode
 from smnp.error.runtime import RuntimeException
 from smnp.type.model import Type
 
@@ -73,12 +74,14 @@ def evaluate(node, environment):
     from smnp.runtime.evaluators.extend import ExtendEvaluator
     from smnp.runtime.evaluators.block import BlockEvaluator
     from smnp.runtime.evaluators.imports import ImportEvaluator
+    from smnp.runtime.evaluators.function import ReturnEvaluator
     result = Evaluator.oneOf(
         Evaluator.forNodes(ProgramEvaluator.evaluate, Program),
         Evaluator.forNodes(ImportEvaluator.evaluate, ImportNode),
         Evaluator.forNodes(FunctionDefinitionEvaluator.evaluate, FunctionDefinitionNode),
         Evaluator.forNodes(ExtendEvaluator.evaluate, ExtendNode),
         Evaluator.forNodes(BlockEvaluator.evaluate, BlockNode),
+        Evaluator.forNodes(ReturnEvaluator.evaluate, ReturnNode),
         expressionEvaluator()
     )(node, environment)
 

smnp/runtime/evaluators/function.py

@@ -1,4 +1,3 @@
-from smnp.ast.node.ret import ReturnNode
 from smnp.error.runtime import RuntimeException
 from smnp.runtime.evaluator import Evaluator, evaluate
 from smnp.runtime.evaluators.expression import expressionEvaluator
@@ -38,9 +37,17 @@ class BodyEvaluator(Evaluator):
     @classmethod
     def evaluator(cls, node, environment):
         for child in node.children:
-            if type(child) == ReturnNode:
-                x = expressionEvaluator(doAssert=True)(child.value, environment).value #TODO check if it isn't necessary to verify 'result' attr of EvaluatioNResult
-                return x
-            else:
-                evaluate(child, environment)
+            evaluate(child, environment)
+            if environment.callStack[-1].value is not None:
+                return environment.callStack[-1].value
 
+
+class ReturnEvaluator(Evaluator):
+
+    @classmethod
+    def evaluator(cls, node, environment):
+        if len(environment.callStack) > 0:
+            returnValue = expressionEvaluator(doAssert=True)(node.value, environment)
+            environment.callStack[-1].value = returnValue.value
+        else:
+            raise RuntimeException("Cannot use 'return' statement outside a function or method", node.pos, environment)