src/Typecheck.hs

@@ -21,7 +21,7 @@ typeCheckMethodDeclaration (MethodDeclaration retType name params body) classFie
     let
         -- Combine class fields with method parameters to form the initial symbol table for the method
         methodParams = [(identifier, dataType) | ParameterDeclaration dataType identifier <- params]
-        initialSymtab = classFields ++ methodParams
+        initialSymtab =  ("thisMeth", retType) : classFields ++ methodParams
         checkedBody = typeCheckStatement body initialSymtab classes
         bodyType = getTypeFromStmt checkedBody
         -- Check if the type of the body matches the declared return type
@@ -37,6 +37,7 @@ typeCheckExpression (CharacterLiteral c) _ _ = TypedExpression "char" (Character
 typeCheckExpression (BooleanLiteral b) _ _ = TypedExpression "boolean" (BooleanLiteral b)
 typeCheckExpression NullLiteral _ _ = TypedExpression "null" NullLiteral
 typeCheckExpression (Reference id) symtab classes =
+  -- TODO: maybe maje exception for "this" in first lookup?
   case lookup id symtab of
     Just t -> TypedExpression t (LocalVariable id)
     Nothing ->
@@ -208,12 +209,16 @@ typeCheckStatement (If cond thenStmt elseStmt) symtab classes =
       elseStmt' = case elseStmt of
         Just stmt -> Just (typeCheckStatement stmt symtab classes)
         Nothing   -> Nothing
+      thenType = getTypeFromStmt thenStmt'
+      elseType = maybe "void" getTypeFromStmt elseStmt'
+      ifType = if thenType /= "void" && elseType /= "void" && thenType == elseType then thenType else "void"
    in if getTypeFromExpr cond' == "boolean"
         then
-          TypedStatement (getTypeFromStmt thenStmt') (If cond' thenStmt' elseStmt')
+          TypedStatement ifType (If cond' thenStmt' elseStmt')
         else
           error "If condition must be of type boolean"
 
+
 typeCheckStatement (LocalVariableDeclaration (VariableDeclaration dataType identifier maybeExpr)) symtab classes =
     -- Check for redefinition in the current scope
     if any ((== identifier) . snd) symtab