fix increment

Test/TestParser.hs

@@ -139,16 +139,16 @@ testExpressionOr = TestCase $
     assertEqual "expect or expression" (BinaryOperation Or (Reference "bar") (Reference "baz")) $
     parseExpression [IDENTIFIER "bar",OR,IDENTIFIER "baz"]
 testExpressionPostIncrement = TestCase $
-    assertEqual "expect PostIncrement" (UnaryOperation PostIncrement (Reference "a")) $
+    assertEqual "expect PostIncrement" (StatementExpressionExpression $ PostIncrement (Reference "a")) $
     parseExpression [IDENTIFIER "a",INCREMENT]
 testExpressionPostDecrement = TestCase $
-    assertEqual "expect PostDecrement" (UnaryOperation PostDecrement (Reference "a")) $
+    assertEqual "expect PostDecrement" (StatementExpressionExpression $ PostDecrement (Reference "a")) $
     parseExpression [IDENTIFIER "a",DECREMENT]
 testExpressionPreIncrement = TestCase $
-    assertEqual "expect PreIncrement" (UnaryOperation PreIncrement (Reference "a")) $
+    assertEqual "expect PreIncrement" (StatementExpressionExpression $ PreIncrement (Reference "a")) $
     parseExpression [INCREMENT,IDENTIFIER "a"]
 testExpressionPreDecrement = TestCase $
-    assertEqual "expect PreIncrement" (UnaryOperation PreDecrement (Reference "a")) $
+    assertEqual "expect PreIncrement" (StatementExpressionExpression $ PreDecrement (Reference "a")) $
     parseExpression [DECREMENT,IDENTIFIER "a"]
 testExpressionAssign = TestCase $
     assertEqual "expect assign 5 to a" (StatementExpressionExpression (Assignment (Reference "a") (IntegerLiteral 5))) $

src/Ast.hs

@@ -24,6 +24,10 @@ data StatementExpression
   | ConstructorCall DataType [Expression]
   | MethodCall Expression Identifier [Expression]
   | TypedStatementExpression DataType StatementExpression
+  | PostIncrement Expression
+  | PostDecrement Expression
+  | PreIncrement Expression
+  | PreDecrement Expression
   deriving (Show, Eq)
 
 data BinaryOperator
@@ -49,10 +53,6 @@ data BinaryOperator
 data UnaryOperator
   = Not
   | Minus
-  | PostIncrement
-  | PostDecrement
-  | PreIncrement
-  | PreDecrement
   deriving (Show, Eq)
 
 data Expression

src/Example.hs

@@ -101,6 +101,18 @@ exampleNameResolutionAssignment = Block [
 exampleCharIntOperation :: Expression
 exampleCharIntOperation = BinaryOperation Addition (CharacterLiteral 'a') (IntegerLiteral 1)
 
+exampleNullDeclaration :: Statement
+exampleNullDeclaration = LocalVariableDeclaration (VariableDeclaration "Person" "bob" (Just NullLiteral))
+
+exampleNullDeclarationFail :: Statement
+exampleNullDeclarationFail = LocalVariableDeclaration (VariableDeclaration "int" "a" (Just NullLiteral))
+
+exampleNullAssignment :: Statement
+exampleNullAssignment = StatementExpressionStatement (Assignment (Reference "a") NullLiteral)
+
+exampleIncrement :: Statement
+exampleIncrement = StatementExpressionStatement (PostIncrement (Reference "a"))
+
 testClasses :: [Class]
 testClasses = [
     Class "Person" [
@@ -226,3 +238,30 @@ runTypeCheck = do
         printResult "Result Char Int Operation:" evaluatedCharIntOperation
         ) handleError
 
+    catch (do
+        print "====================================================================================="
+        evaluatedNullDeclaration <- evaluate (typeCheckStatement exampleNullDeclaration [] sampleClasses)
+        printSuccess "Type checking of null declaration completed successfully"
+        printResult "Result Null Declaration:" evaluatedNullDeclaration
+        ) handleError
+
+    catch (do
+        print "====================================================================================="
+        evaluatedNullDeclarationFail <- evaluate (typeCheckStatement exampleNullDeclarationFail [] sampleClasses)
+        printSuccess "Type checking of null declaration failed"
+        printResult "Result Null Declaration:" evaluatedNullDeclarationFail
+        ) handleError
+
+    catch (do
+        print "====================================================================================="
+        evaluatedNullAssignment <- evaluate (typeCheckStatement exampleNullAssignment [("a", "Person")] sampleClasses)
+        printSuccess "Type checking of null assignment completed successfully"
+        printResult "Result Null Assignment:" evaluatedNullAssignment
+        ) handleError
+
+    catch (do
+        print "====================================================================================="
+        evaluatedIncrement <- evaluate (typeCheckStatement exampleIncrement [("a", "int")] sampleClasses)
+        printSuccess "Type checking of increment completed successfully"
+        printResult "Result Increment:" evaluatedIncrement
+        ) handleError

src/Parser/JavaParser.y

@@ -279,13 +279,13 @@ assignmentoperator : ASSIGN { Nothing }
                  | XOREQUAL { Just BitwiseXor }
                  | OREQUAL{ Just BitwiseOr }
 
-preincrementexpression : INCREMENT unaryexpression { UnaryOperation PreIncrement $2 }
+preincrementexpression : INCREMENT unaryexpression { PreIncrement $2 }
 
-predecrementexpression : DECREMENT unaryexpression { UnaryOperation PreDecrement $2 }
+predecrementexpression : DECREMENT unaryexpression { PreDecrement $2 }
 
-postincrementexpression : postfixexpression INCREMENT { UnaryOperation PostIncrement $1 }
+postincrementexpression : postfixexpression INCREMENT { PostIncrement $1 }
 
-postdecrementexpression : postfixexpression DECREMENT { UnaryOperation PostDecrement $1 }
+postdecrementexpression : postfixexpression DECREMENT { PostDecrement $1 }
 
 methodinvocation : simplename LBRACE   RBRACE  { MethodCall (Reference "this") $1 []  }
                  | simplename LBRACE argumentlist RBRACE { MethodCall (Reference "this") $1 $3 }
@@ -300,15 +300,15 @@ conditionalandexpression : inclusiveorexpression { $1 }
 fieldaccess      : primary  DOT IDENTIFIER { }
 
 unaryexpression         : unaryexpressionnotplusminus { $1 }
-                 | predecrementexpression { $1 }
+                 | predecrementexpression { StatementExpressionExpression $1 }
                  | PLUS unaryexpression { $2 }
                  | MINUS unaryexpression { UnaryOperation Minus $2 }
-                 | preincrementexpression { $1 }
+                 | preincrementexpression { StatementExpressionExpression $1 }
 
 postfixexpression : primary { $1 }
                  | name { $1 }
-                 | postincrementexpression { $1 }
-                 | postdecrementexpression{ $1 }
+                 | postincrementexpression { StatementExpressionExpression $1 }
+                 | postdecrementexpression { StatementExpressionExpression $1 }
 
 primary                 : primarynonewarray { $1 }
 

src/Typecheck.hs

@@ -25,7 +25,7 @@ typeCheckMethodDeclaration (MethodDeclaration retType name params body) classFie
         checkedBody = typeCheckStatement body initialSymtab classes
         bodyType = getTypeFromStmt checkedBody
         -- Check if the type of the body matches the declared return type
-    in if bodyType == retType || (bodyType == "void" && retType == "void")
+    in if bodyType == retType || (bodyType == "void" && retType == "void") || (bodyType == "null" && isObjectType retType)
        then MethodDeclaration retType name params checkedBody
        else error $ "Return type mismatch in method " ++ name ++ ": expected " ++ retType ++ ", found " ++ bodyType
 
@@ -89,50 +89,11 @@ typeCheckExpression (UnaryOperation op expr) symtab classes =
             else
               error "Logical NOT operation requires an operand of type boolean"
         Minus ->
-          if type' == "int"
+          if type' == "int" || type' == "char"
             then
-              TypedExpression "int" (UnaryOperation op expr')
-          else if type' == "char"
-            then
-              TypedExpression "char" (UnaryOperation op expr')
+              TypedExpression type' (UnaryOperation op expr')
             else
               error "Unary minus operation requires an operand of type int or char"
-        PostIncrement ->
-          if type' == "int"
-            then
-              TypedExpression "int" (UnaryOperation op expr')
-          else if type' == "char"
-            then
-              TypedExpression "char" (UnaryOperation op expr')
-            else
-              error "Post-increment operation requires an operand of type int or char"
-        PostDecrement ->
-          if type' == "int"
-            then
-              TypedExpression "int" (UnaryOperation op expr')
-          else if type' == "char"
-            then
-              TypedExpression "char" (UnaryOperation op expr')
-            else
-              error "Post-decrement operation requires an operand of type int or char"
-        PreIncrement ->
-          if type' == "int"
-            then
-              TypedExpression "int" (UnaryOperation op expr')
-          else if type' == "char"
-            then
-              TypedExpression "char" (UnaryOperation op expr')
-            else
-              error "Pre-increment operation requires an operand of type int or char"
-        PreDecrement ->
-          if type' == "int"
-            then
-              TypedExpression "int" (UnaryOperation op expr')
-          else if type' == "char"
-            then
-              TypedExpression "char" (UnaryOperation op expr')
-            else
-              error "Pre-decrement operation requires an operand of type int or char"
 
 typeCheckExpression (StatementExpressionExpression stmtExpr) symtab classes =
   let stmtExpr' = typeCheckStatementExpression stmtExpr symtab classes
@@ -147,8 +108,8 @@ typeCheckStatementExpression (Assignment ref expr) symtab classes =
       type' = getTypeFromExpr expr'
       type'' = getTypeFromExpr ref'
   in
-      if type'' == type' then
-        TypedStatementExpression type' (Assignment ref' expr')
+    if type'' == type' || (type' == "null" && isObjectType type'') then
+      TypedStatementExpression type'' (Assignment ref' expr')
     else
       error $ "Type mismatch in assignment to variable: expected " ++ type'' ++ ", found " ++ type'
 
@@ -202,6 +163,42 @@ typeCheckStatementExpression (MethodCall expr methodName args) symtab classes =
                 Nothing -> error $ "Class for object type '" ++ objType ++ "' not found."
         _ -> error "Invalid object type for method call. Object must have a class type."
 
+typeCheckStatementExpression (PostIncrement expr) symtab classes =
+  let expr' = typeCheckExpression expr symtab classes
+      type' = getTypeFromExpr expr'
+   in if type' == "int" || type' == "char"
+        then
+          TypedStatementExpression type' (PostIncrement expr')
+        else
+          error "Post-increment operation requires an operand of type int or char"
+
+typeCheckStatementExpression (PostDecrement expr) symtab classes =
+  let expr' = typeCheckExpression expr symtab classes
+      type' = getTypeFromExpr expr'
+   in if type' == "int" || type' == "char"
+        then
+          TypedStatementExpression type' (PostDecrement expr')
+        else
+          error "Post-decrement operation requires an operand of type int or char"
+
+typeCheckStatementExpression (PreIncrement expr) symtab classes =
+  let expr' = typeCheckExpression expr symtab classes
+      type' = getTypeFromExpr expr'
+   in if type' == "int" || type' == "char"
+        then
+          TypedStatementExpression type' (PreIncrement expr')
+        else
+          error "Pre-increment operation requires an operand of type int or char"
+
+typeCheckStatementExpression (PreDecrement expr) symtab classes =
+  let expr' = typeCheckExpression expr symtab classes
+      type' = getTypeFromExpr expr'
+   in if type' == "int" || type' == "char"
+        then
+          TypedStatementExpression type' (PreDecrement expr')
+        else
+          error "Pre-decrement operation requires an operand of type int or char"
+
 -- ********************************** Type Checking: Statements **********************************
 
 typeCheckStatement :: Statement -> [(Identifier, DataType)] -> [Class] -> Statement
@@ -226,8 +223,12 @@ typeCheckStatement (LocalVariableDeclaration (VariableDeclaration dataType ident
         let checkedExpr = fmap (\expr -> typeCheckExpression expr symtab classes) maybeExpr
             exprType = fmap getTypeFromExpr checkedExpr
         in case exprType of
-            Just t | t /= dataType -> error $ "Type mismatch in declaration of '" ++ identifier ++ "': expected " ++ dataType ++ ", found " ++ t
-            _ -> TypedStatement dataType (LocalVariableDeclaration (VariableDeclaration dataType identifier checkedExpr))
+            Just t
+                | t == "null" && isObjectType dataType -> 
+                    TypedStatement dataType (LocalVariableDeclaration (VariableDeclaration dataType identifier checkedExpr))
+                | t /= dataType -> error $ "Type mismatch in declaration of '" ++ identifier ++ "': expected " ++ dataType ++ ", found " ++ t
+                | otherwise -> TypedStatement dataType (LocalVariableDeclaration (VariableDeclaration dataType identifier checkedExpr))
+            Nothing -> TypedStatement dataType (LocalVariableDeclaration (VariableDeclaration dataType identifier checkedExpr))
 
 typeCheckStatement (While cond stmt) symtab classes =
   let cond' = typeCheckExpression cond symtab classes
@@ -254,6 +255,7 @@ typeCheckStatement (Block statements) symtab classes =
                 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] else types)
+                Block _ -> (accSts ++ [checkedStmt], currentSymtab, if stmtType /= "void" then types ++ [stmtType] else types)
                 _ -> (accSts ++ [checkedStmt], currentSymtab, types)
 
         -- Initial accumulator: empty statements list, initial symbol table, empty types list
@@ -278,6 +280,9 @@ typeCheckStatement (StatementExpressionStatement stmtExpr) symtab classes =
 
 -- ********************************** Type Checking: Helpers **********************************
 
+isObjectType :: DataType -> Bool
+isObjectType dt = dt /= "int" && dt /= "boolean" && dt /= "char"
+
 getTypeFromExpr :: Expression -> DataType
 getTypeFromExpr (TypedExpression t _) = t
 getTypeFromExpr _ = error "Untyped expression found where typed was expected"