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slight optimization in GF.Grammar.Lexer

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krasimir
2009-11-17 21:49:51 +00:00
parent d4ac17b9d2
commit a01faec4f9
1 changed files with 5 additions and 5 deletions
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10
src/GF/Grammar/Lexer.x
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@@ -234,23 +234,23 @@ data AlexInput = AI {-# UNPACK #-} !Posn -- current position,
{-# UNPACK #-} !BS.ByteString -- current input string {-# UNPACK #-} !BS.ByteString -- current input string
data ParseResult a data ParseResult a
= POk AlexInput a = POk a
| PFailed Posn -- The position of the error | PFailed Posn -- The position of the error
String -- The error message String -- The error message
newtype P a = P { unP :: AlexInput -> ParseResult a } newtype P a = P { unP :: AlexInput -> ParseResult a }
instance Monad P where instance Monad P where
return a = a `seq` (P $ \s -> POk s a) return a = a `seq` (P $ \s -> POk a)
(P m) >>= k = P $ \ s -> case m s of (P m) >>= k = P $ \ s -> case m s of
POk s1 a -> unP (k a) s1 POk a -> unP (k a) s
PFailed posn err -> PFailed posn err PFailed posn err -> PFailed posn err
fail msg = P $ \(AI posn _ _) -> PFailed posn msg fail msg = P $ \(AI posn _ _) -> PFailed posn msg
runP :: P a -> BS.ByteString -> Either (Posn,String) a runP :: P a -> BS.ByteString -> Either (Posn,String) a
runP (P f) txt = runP (P f) txt =
case f (AI (Pn 1 0) ' ' txt) of case f (AI (Pn 1 0) ' ' txt) of
POk _ x -> Right x POk x -> Right x
PFailed pos msg -> Left (pos,msg) PFailed pos msg -> Left (pos,msg)
failLoc :: Posn -> String -> P a failLoc :: Posn -> String -> P a
@@ -267,6 +267,6 @@ lexer cont = P go
AlexToken inp' len act -> unP (cont (act pos (BS.take len str))) inp' AlexToken inp' len act -> unP (cont (act pos (BS.take len str))) inp'
getPosn :: P Posn getPosn :: P Posn
getPosn = P $ \inp@(AI pos _ _) -> POk inp pos getPosn = P $ \inp@(AI pos _ _) -> POk pos
} }