From 666fb4ee1a1beed363102aae90401445aeca1aca Mon Sep 17 00:00:00 2001
From: Fabian Noll <i22024@hb.dhbw-stuttgart.de>
Date: Tue, 14 May 2024 10:04:00 +0200
Subject: [PATCH] Assignment now rakes expression instead of identifier

---
 src/Ast.hs       |  2 +-
 src/Example.hs   | 19 ++++++++++++++++---
 src/Typecheck.hs | 19 +++++++++----------
 3 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/src/Ast.hs b/src/Ast.hs
index 90dcc43..cce19aa 100644
--- a/src/Ast.hs
+++ b/src/Ast.hs
@@ -19,7 +19,7 @@ data Statement
   deriving (Show)
 
 data StatementExpression
-  = Assignment Identifier Expression
+  = Assignment Expression Expression
   | ConstructorCall DataType [Expression]
   | MethodCall Expression Identifier [Expression]
   | TypedStatementExpression DataType StatementExpression
diff --git a/src/Example.hs b/src/Example.hs
index 5c9cb51..e36c64d 100644
--- a/src/Example.hs
+++ b/src/Example.hs
@@ -49,7 +49,7 @@ exampleExpression :: Expression
 exampleExpression = BinaryOperation NameResolution (Reference "bob") (Reference "age")
 
 exampleAssignment :: Expression
-exampleAssignment = StatementExpressionExpression (Assignment "a" (IntegerLiteral 30))
+exampleAssignment = StatementExpressionExpression (Assignment (Reference "a") (IntegerLiteral 30))
 
 exampleMethodCall :: Statement
 exampleMethodCall = StatementExpressionStatement (MethodCall (Reference "this") "setAge" [IntegerLiteral 30])
@@ -80,7 +80,7 @@ exampleMethodCallAndAssignment = Block [
     LocalVariableDeclaration (VariableDeclaration "int" "age" (Just (StatementExpressionExpression (MethodCall (Reference "bob") "getAge" [])))),
     StatementExpressionStatement (MethodCall (Reference "bob") "setAge" [IntegerLiteral 30]),
     LocalVariableDeclaration (VariableDeclaration "int" "a" Nothing),
-    StatementExpressionStatement (Assignment "a" (Reference "age"))
+    StatementExpressionStatement (Assignment (Reference "a") (Reference "age"))
     ]
 
 
@@ -89,7 +89,13 @@ exampleMethodCallAndAssignmentFail = Block [
     LocalVariableDeclaration (VariableDeclaration "Person" "bob" (Just (StatementExpressionExpression  (ConstructorCall "Person" [IntegerLiteral 30])))),
     LocalVariableDeclaration (VariableDeclaration "int" "age" (Just (StatementExpressionExpression (MethodCall (Reference "bob") "getAge" [])))),
     StatementExpressionStatement (MethodCall (Reference "bob") "setAge" [IntegerLiteral 30]),
-    StatementExpressionStatement (Assignment "a" (Reference "age"))
+    StatementExpressionStatement (Assignment (Reference "age") (Reference "age"))
+    ]
+
+exampleNameResolutionAssignment :: Statement
+exampleNameResolutionAssignment = Block [
+    LocalVariableDeclaration (VariableDeclaration "Person" "bob" (Just (StatementExpressionExpression  (ConstructorCall "Person" [IntegerLiteral 30])))),
+    StatementExpressionStatement (Assignment (BinaryOperation NameResolution (Reference "bob") (Reference "age")) (IntegerLiteral 30))
     ]
 
 testClasses :: [Class]
@@ -202,4 +208,11 @@ runTypeCheck = do
         printSuccess "Type checking of Program completed successfully"
         printResult "Typed Program:" typedProgram
         ) handleError
+    
+    catch (do
+        print "====================================================================================="
+        typedAssignment <- evaluate (typeCheckStatement exampleNameResolutionAssignment [] sampleClasses)
+        printSuccess "Type checking of name resolution assignment completed successfully"
+        printResult "Result Name Resolution Assignment:" typedAssignment
+        ) handleError
 
diff --git a/src/Typecheck.hs b/src/Typecheck.hs
index 981d4d8..0346c5d 100644
--- a/src/Typecheck.hs
+++ b/src/Typecheck.hs
@@ -200,18 +200,17 @@ typeCheckExpression (StatementExpressionExpression stmtExpr) symtab classes =
 -- ********************************** Type Checking: StatementExpressions **********************************
 
 typeCheckStatementExpression :: StatementExpression -> [(Identifier, DataType)] -> [Class] -> StatementExpression
-typeCheckStatementExpression (Assignment id expr) symtab classes =
+typeCheckStatementExpression (Assignment ref expr) symtab classes =
   let expr' = typeCheckExpression expr symtab classes
+      ref' = typeCheckExpression ref symtab classes
       type' = getTypeFromExpr expr'
-      maybeType'' = lookupType id symtab
-   in case maybeType'' of
-        Just type'' ->
-          if type' == type'' then
-            TypedStatementExpression type' (Assignment id expr')
-          else
-            error $ "Assignment type mismatch: expected " ++ type'' ++ ", found " ++ type'
-        Nothing -> error $ "Identifier '" ++ id ++ "' not found in symbol table"
-
+      type'' = getTypeFromExpr ref'
+    in
+      if type'' == type' then 
+        TypedStatementExpression type' (Assignment ref' expr')
+      else
+        error $ "Type mismatch in assignment to variable: expected " ++ type'' ++ ", found " ++ type'
+          
 typeCheckStatementExpression (ConstructorCall className args) symtab classes =
   case find (\(Class name _ _) -> name == className) classes of
     Nothing -> error $ "Class '" ++ className ++ "' not found."