From 70b68c91e008efb7a7b5baf638140cb76380f931 Mon Sep 17 00:00:00 2001
From: "Juan J. Martinez" <jjm@usebox.net>
Date: Sun, 4 Sep 2022 08:31:51 +0100
Subject: Refactored typecheck value

---
 src/Compiler.hs | 33 ++++++++++++++++-----------------
 1 file changed, 16 insertions(+), 17 deletions(-)

(limited to 'src')

diff --git a/src/Compiler.hs b/src/Compiler.hs
index 40e5f73..f0169be 100644
--- a/src/Compiler.hs
+++ b/src/Compiler.hs
@@ -64,20 +64,25 @@ showMaybet :: Maybe A.Type -> String
 showMaybet Nothing = "()"
 showMaybet (Just t) = show t
 
--- | @typecheckReturn value fret@ resolves @value@ and compares it with @fret@,
--- returning a string decribing an error or Nothing in case of a type match.
-typecheckReturn :: Maybe A.Expr -> Maybe A.Type -> State CompState (Maybe String)
-typecheckReturn Nothing Nothing = return $ Nothing
-typecheckReturn Nothing fret = return $ Just $ "invalid return value\n     found: ()\n  expected: " ++ showMaybet fret
-typecheckReturn (Just value) fret = do
+-- | @typecheckVal value typ@ resolves @value@ and compares it to @typ@ type,
+-- returning a string describing an error or Nothin in case of type match.
+typecheckVal :: A.Expr -> Maybe A.Type -> State CompState (Maybe String)
+typecheckVal value typ = do
   r <- compile value
   case r of
     Right r ->
-      if r == fret
+      if r == typ
         then return $ Nothing
-        else return $ Just $ "invalid return value\n     found: " ++ showMaybet r ++ "\n  expected: " ++ showMaybet fret
+        else return $ Just $ "type mismatch\n     found: " ++ showMaybet r ++ "\n  expected: " ++ showMaybet typ
     Left _ -> return $ Nothing -- error resolving return value
 
+-- | @typecheckReturn value fret@ resolves @value@ and compares it with @fret@,
+-- returning a string decribing an error or Nothing in case of a type match.
+typecheckReturn :: Maybe A.Expr -> Maybe A.Type -> State CompState (Maybe String)
+typecheckReturn Nothing Nothing = return $ Nothing
+typecheckReturn Nothing fret = return $ Just $ "invalid return value\n     found: ()\n  expected: " ++ showMaybet fret
+typecheckReturn (Just value) fret = typecheckVal value fret
+
 -- built-in types
 types = ["bool", "u8", "s8", "u16", "s16"]
 
@@ -153,16 +158,10 @@ compile x = do
           if not (definedType typ)
             then Error UndefinedType ("undefined type in variable declaration \"" ++ ident ++ "\"") pos : errs
             else errs
-      -- type-check value
-      vt <- compile val
+      vt <- typecheckVal val $ Just typ
       errs <- case vt of
-        Right (Just t) ->
-          if t == typ
-            then return $ errs
-            else return $ (Error TypeError ("value type mismatch\n     found: " ++ show t ++ "\n  expected: " ++ show typ) pos) : errs
-        _ -> do
-          (_, errs) <- get -- error resolving value
-          return $ errs
+        Just err -> return $ Error TypeError err pos : errs
+        Nothing -> return $ errs
       put (ev, errs)
       return $ Right $ Just typ
     (A.Return value pos) -> do
-- 
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