From d5a4bcd8e40597af85a31fe830760d1f0791e35d Mon Sep 17 00:00:00 2001
From: pycsham <shampuiyanchloe@gmail.com>
Date: Fri, 6 Mar 2020 18:53:45 -0500
Subject: [PATCH] implemented method return type checking
---
AST.py | 18 ++++++++++++++++++
LineNodes.py | 2 +-
MemberNodes.py | 32 ++++++++++++++++++++++++++++++--
3 files changed, 49 insertions(+), 3 deletions(-)
diff --git a/AST.py b/AST.py
index 7a67a49..885000e 100644
--- a/AST.py
+++ b/AST.py
@@ -108,3 +108,21 @@ def getParseTreeNodes(names, tree, terminateList = []):
else:
result.extend(getParseTreeNodes(names, n, terminateList))
return result
+
+def getASTNode(names, AST):
+ result = []
+ if not AST:
+ return result
+ if AST.__class__.__name__ in names:
+ result.append(AST)
+ return result
+ if not AST.children:
+ return []
+ for n in AST.children:
+ if not n:
+ continue
+ if n.__class__.__name__ in names:
+ result.append(n)
+ else:
+ result.extend(getASTNode(names, n))
+ return result
diff --git a/LineNodes.py b/LineNodes.py
index 52f1a02..57d091e 100644
--- a/LineNodes.py
+++ b/LineNodes.py
@@ -209,7 +209,7 @@ class ReturnNode(ASTNode):
self.expr.checkType()
self.myType = self.expr.myType
else:
- self.myType = TypeStruct("void", None)
+ self.myType = None # this is None as returning a value of type Void is invalid even in a function with type Void
# forStatement and forStatementNoShortIf
# Rules:
diff --git a/MemberNodes.py b/MemberNodes.py
index 13ba951..4eeabd1 100644
--- a/MemberNodes.py
+++ b/MemberNodes.py
@@ -1,4 +1,4 @@
-from AST import ASTNode, getParseTreeNodes
+from AST import ASTNode, getParseTreeNodes, getASTNode
from LineNodes import BlockNode, VarDclNode
from ExprPrimaryNodes import makeNodeFromExpr
from UnitNodes import ParamNode
@@ -107,9 +107,37 @@ class MethodNode(ASTNode):
return env
def checkType(self):
- if self.methodType: # constructor
+ if self.methodType: # constructor would be None
self.myType = self.methodType.myType
for p in self.params:
p.checkType()
if self.body:
self.body.checkType()
+
+ # Checking return types against the function type
+ # No method body: do not check type as function isn't implemented
+ if not self.body:
+ return
+
+ # With method body
+ returnNodes = getASTNode(["ReturnNode"], self.body)
+
+ # Checking for cases where there are no return statements
+ if not returnNodes:
+ # Either a constructor or the function has type Void
+ if not self.methodType or self.myType.name == "void":
+ return
+ raise Exception("ERROR: no return statement at function {}".format(self.name))
+
+ # Checking for cases where there are return statements
+ for n in returnNodes:
+ # Checking for functions of type void
+ # Only valid if either the function doesn't have a return statement(checked above), or the return statement is a semicolon (return;)
+ if self.myType.name == "void":
+ if n.myType:
+ raise Exception("ERROR: return type of function {} doesn't match with return statement.".format(self.name))
+
+ # Checking for non void cases
+ if not self.myType.assignable(n.myType):
+ raise Exception("ERROR: return type of function {} doesn't match with return statement.".format(self.name))
+ return
\ No newline at end of file
--
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