add full block type checking

src/Ast.hs

@@ -265,35 +265,27 @@ typeCheckStatement (While cond stmt) symtab classes =
 
 typeCheckStatement (Block statements) symtab classes =
     let
-        -- Helper function to process each statement and manage the symbol table
-        processStatements (accSts, currentSymtab) stmt =
-            case stmt of
+        processStatements (accSts, currentSymtab, types) stmt =
+            let
+                checkedStmt = typeCheckStatement stmt currentSymtab classes
+                stmtType = getTypeFromStmt checkedStmt
+            in case stmt of
                 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)
+                    in (accSts ++ [checkedStmt], newSymtab, types)
 
-                _ ->
-                    -- For other statements, just type check using the current symbol table
-                    let checkedStmt = typeCheckStatement stmt currentSymtab classes
-                    in (accSts ++ [checkedStmt], currentSymtab)
+                If {} -> (accSts ++ [checkedStmt], currentSymtab, if stmtType /= "Void" then types ++ [stmtType] else types)
+                While _ _ -> (accSts ++ [checkedStmt], currentSymtab, if stmtType /= "Void" then types ++ [stmtType] else types)
+                Return _ -> (accSts ++ [checkedStmt], currentSymtab, if stmtType /= "Void" then types ++ [stmtType])
+                _ -> (accSts ++ [checkedStmt], currentSymtab, types)
 
-        -- Fold over the list of statements starting with the initial symbol table
-        (checkedStatements, finalSymtab) = foldl processStatements ([], symtab) statements
+        -- Initial accumulator: empty statements list, initial symbol table, empty types list
+        (checkedStatements, finalSymtab, collectedTypes) = foldl processStatements ([], symtab, []) statements
 
-        -- 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
+        -- Determine the block's type: unify all collected types, default to "Void" if none
+        blockType = if null collectedTypes then "Void" else foldl1 unifyReturnTypes collectedTypes
 
     in TypedStatement blockType (Block checkedStatements)
 
@@ -307,7 +299,7 @@ typeCheckStatement (Return expr) symtab classes =
         Nothing -> Nothing
    in case expr' of
         Just e' -> TypedStatement (getTypeFromExpr e') (Return (Just e'))
-        Nothing -> TypedStatement "void" (Return Nothing)
+        Nothing -> TypedStatement "Void" (Return Nothing)
 
 -- ********************************** Type Checking: Helpers **********************************