Merge pull request #38 from scmlab/remove_unused_either_in_lexer

Remove unused either in lexer

Author: scmu

gcl/src/Server/Handler/GCL/Refine.hs

@@ -279,13 +279,11 @@ digImplHoles parseStart filePath implText =
 parseFragment :: Pos -> Text -> Either ParseError [C.Stmt]
 parseFragment fragmentStart fragment = do
   let Pos filePath _ _ _ = fragmentStart
-  case Syntax.Parser.Lexer.scan filePath fragment of
-    Left err -> Left (LexicalError err)
-    Right tokens -> do
-      let tokens' = translateTokStream fragmentStart tokens
-      case Parser.parse Parser.statements filePath tokens' of
-        Left (errors, logMsg) -> Left (SyntacticError errors logMsg)
-        Right val -> Right val
+  let tokens = Syntax.Parser.Lexer.scan filePath fragment
+  let tokens' = translateTokStream fragmentStart tokens
+  case Parser.parse Parser.statements filePath tokens' of
+    Left (errors, logMsg) -> Left (SyntacticError errors logMsg)
+    Right val -> Right val
   where
     translateRange :: Pos -> Pos -> Pos
     translateRange

gcl/src/Syntax/Parser.hs

@@ -44,11 +44,11 @@ type Parser = ParsecT Void TokStream M
 --------------------------------------------------------------------------------
 
 scanAndParse :: Parser a -> FilePath -> Text -> Either ParseError a
-scanAndParse parser filepath source = case scan filepath source of
-  Left err -> throwError (LexicalError err)
-  Right tokens -> case parse parser filepath tokens of
-    Left (errors, logMsg) -> throwError (SyntacticError errors logMsg)
-    Right val -> return val
+scanAndParse parser filepath source =
+  let tokens = scan filepath source
+   in case parse parser filepath tokens of
+        Left (errors, logMsg) -> throwError (SyntacticError errors logMsg)
+        Right val -> return val
 
 parse :: Parser a -> FilePath -> TokStream -> Either (NonEmpty (Loc, String), String) a
 parse parser filepath tokenStream =

gcl/src/Syntax/Parser/Lexer.hs

@@ -483,23 +483,20 @@ lexer =
 --------------------------------------------------------------------------------
 type LexicalError = Pos
 
-scan :: FilePath -> Text -> Either LexicalError TokStream
+scan :: FilePath -> Text -> TokStream
 scan filepath =
-  translateLoc . Right . runLexer lexer filepath . Text.unpack
+  translateLoc . runLexer lexer filepath . Text.unpack
   where
     -- According to the document in Data.Loc.Range, the original meaning of Loc is
     -- different from how we use it as Range (to simply put, Range extends 1 in col and charOffset).
     -- The lexer records tokens' ranges in Loc, and we use translateLoc to make it Range.
-    translateLoc :: Either LexicalError TokStream -> Either LexicalError TokStream
-    translateLoc (Left x) = Left x
-    translateLoc (Right toks) = Right (f toks)
+    translateLoc :: TokStream -> TokStream
+    translateLoc (TsToken (L loc x) rest) = TsToken (L (update loc) x) (translateLoc rest)
       where
-        f (TsToken (L loc x) rest) = TsToken (L (update loc) x) (f rest)
-          where
-            update NoLoc = NoLoc
-            update (Loc start (Pos path l c co)) = Loc start (Pos path l (c + 1) (co + 1))
-        f TsEof = TsEof
-        f (TsError e) = TsError e
+        update NoLoc = NoLoc
+        update (Loc start (Pos path l c co)) = Loc start (Pos path l (c + 1) (co + 1))
+    translateLoc TsEof = TsEof
+    translateLoc (TsError e) = TsError e
 
 -- | Instances of PrettyToken
 instance PrettyToken Tok where