update block and local variable typecheck

src/Ast.hs

@@ -70,14 +70,14 @@ typeCheckClass (Class className methods fields) classes =
     let
         -- Create a symbol table from class fields
         classFields = [(dt, id) | VariableDeclaration dt id _ <- fields]
-        checkedMethods = map (\method -> typeCheckMethodDeclaration method classes classFields) methods
+        checkedMethods = map (\method -> typeCheckMethodDeclaration method classFields classes) methods
     in Class className checkedMethods fields
 
-typeCheckMethodDeclaration :: MethodDeclaration -> [Class] -> [(DataType, Identifier)] -> MethodDeclaration
-typeCheckMethodDeclaration (MethodDeclaration retType name params body) classes classFields =
+typeCheckMethodDeclaration :: MethodDeclaration -> [(DataType, Identifier)] -> [Class] -> MethodDeclaration
+typeCheckMethodDeclaration (MethodDeclaration retType name params body) classFields classes =
     let
         -- Combine class fields with method parameters to form the initial symbol table for the method
-        methodParams = [(dt, id) | ParameterDeclaration dt id <- params]
+        methodParams = [(dataType, identifier) | ParameterDeclaration dataType identifier <- params]
         -- Ensure method parameters shadow class fields if names collide
         initialSymtab = classFields ++ methodParams  
         -- Type check the body of the method using the combined symbol table
@@ -88,6 +88,7 @@ typeCheckMethodDeclaration (MethodDeclaration retType name params body) classes
        then MethodDeclaration retType name params checkedBody
        else error $ "Return type mismatch in method " ++ name ++ ": expected " ++ retType ++ ", found " ++ bodyType
 
+-- ********************************** Type Checking: Expressions **********************************
 
 typeCheckExpression :: Expression -> [(DataType, Identifier)] -> [Class] -> Expression
 typeCheckExpression (IntegerLiteral i) _ _ = TypedExpression "int" (IntegerLiteral i)
@@ -193,6 +194,7 @@ typeCheckExpression (BinaryOperation op expr1 expr2) symtab classes =
               TypedExpression "boolean" (BinaryOperation op expr1' expr2')
             else
               error "Logical OR operation requires two operands of type boolean"
+              -- dont i have to lookup in classes if expr1 is in the list of classes? and if it is, then i have to check if expr2 is a method / variable in that class
         NameResolution -> TypedExpression type1 (BinaryOperation op expr1' expr2')
 
 typeCheckExpression (UnaryOperation op expr) symtab classes =
@@ -216,6 +218,8 @@ typeCheckExpression (StatementExpressionExpression stmtExpr) symtab classes =
   let stmtExpr' = typeCheckStatementExpression stmtExpr symtab classes
    in TypedExpression (getTypeFromStmtExpr stmtExpr') (StatementExpressionExpression stmtExpr')
 
+-- ********************************** Type Checking: StatementExpressions **********************************
+
 typeCheckStatementExpression :: StatementExpression -> [(DataType, Identifier)] -> [Class] -> StatementExpression
 typeCheckStatementExpression (Assignment id expr) symtab classes =
   let expr' = typeCheckExpression expr symtab classes
@@ -235,6 +239,8 @@ typeCheckStatementExpression (MethodCall methodName args) symtab classes =
   let args' = map (\arg -> typeCheckExpression arg symtab classes) args
    in TypedStatementExpression "Object" (MethodCall methodName args')
 
+-- ********************************** Type Checking: Statements **********************************
+
 typeCheckStatement :: Statement -> [(DataType, Identifier)] -> [Class] -> Statement
 typeCheckStatement (If cond thenStmt elseStmt) symtab classes =
   let cond' = typeCheckExpression cond symtab classes
@@ -259,29 +265,42 @@ typeCheckStatement (While cond stmt) symtab classes =
 
 typeCheckStatement (Block statements) symtab classes =
     let
-        processStatements (accSts, retTypes) stmt = 
+        -- Helper function to process each statement and manage the symbol table
+        processStatements (accSts, currentSymtab) stmt =
             case stmt of
-                Return maybeExpr ->
-                    let checkedExpr = fmap (\expr -> typeCheckExpression expr symtab classes) maybeExpr
-                        exprType = case checkedExpr of
-                            Just (TypedExpression dt _) -> dt
-                            Nothing -> "Void" -- Return with no expression is "Void"
-                    in (accSts ++ [Return checkedExpr], retTypes ++ [exprType])
+                LocalVariableDeclaration (VariableDeclaration dataType identifier maybeExpr) ->
+                    let
+                        -- Type check the expression if it exists
+                        checkedExpr = fmap (\expr -> typeCheckExpression expr currentSymtab classes) maybeExpr
+                        
+                        -- Update the symbol table with the new variable
+                        newSymtab = (dataType, identifier) : currentSymtab
+                        newStmt = typeCheckStatement (LocalVariableDeclaration (VariableDeclaration dataType identifier checkedExpr)) newSymtab classes
+                    in (accSts ++ [newStmt], newSymtab)
+
                 _ ->
-                    -- Type check the statment and add it to the accumulator and pass the current return types
-                    let checkedStmt = typeCheckStatement stmt symtab classes
-                    in (accSts ++ [checkedStmt], retTypes)
+                    -- For other statements, just type check using the current symbol table
+                    let checkedStmt = typeCheckStatement stmt currentSymtab classes
+                    in (accSts ++ [checkedStmt], currentSymtab)
 
-        -- Initialize with empty accumulators for statements and return types
-        (checkedStatements, returnTypes) = foldl processStatements ([], []) statements
+        -- Fold over the list of statements starting with the initial symbol table
+        (checkedStatements, finalSymtab) = foldl processStatements ([], symtab) statements
 
-        -- Determine the block type by unifying all return types, default to "Void" if none
-        blockType = case returnTypes of
-            [] -> "Void"
-            _  -> foldl1 unifyReturnTypes returnTypes
+        -- Determine the type of the block by examining the types of return statements
+        blockType = if any isReturnStatement checkedStatements
+                    then foldl1 unifyReturnTypes [getTypeFromStmt s | s <- checkedStatements, isReturnStatement s]
+                    else "Void"
+        
+        -- Function to check if a statement is a return statement
+        isReturnStatement (Return _) = True
+        isReturnStatement _ = False
 
     in TypedStatement blockType (Block checkedStatements)
 
+typeCheckStatement (LocalVariableDeclaration (VariableDeclaration dataType identifier maybeExpr)) symtab classes =
+  let checkedExpr = fmap (\expr -> typeCheckExpression expr symtab classes) maybeExpr
+   in TypedStatement dataType (LocalVariableDeclaration (VariableDeclaration dataType identifier checkedExpr))
+
 typeCheckStatement (Return expr) symtab classes =
   let expr' = case expr of
         Just e  -> Just (typeCheckExpression e symtab classes)
@@ -290,6 +309,8 @@ typeCheckStatement (Return expr) symtab classes =
         Just e' -> TypedStatement (getTypeFromExpr e') (Return (Just e'))
         Nothing -> TypedStatement "void" (Return Nothing)
 
+-- ********************************** Type Checking: Helpers **********************************
+
 getTypeFromExpr :: Expression -> DataType
 getTypeFromExpr (TypedExpression t _) = t
 getTypeFromExpr _ = error "Untyped expression found where typed was expected"