-{-# OPTIONS_GHC -fno-implicit-prelude #-}
+{-# LANGUAGE CPP, NoImplicitPrelude #-}
+
-----------------------------------------------------------------------------
-- |
-- Module : Text.Read.Lex
lexLitChar :: ReadP Lexeme
lexLitChar =
- do char '\''
+ do _ <- char '\''
(c,esc) <- lexCharE
guard (esc || c /= '\'') -- Eliminate '' possibility
- char '\''
+ _ <- char '\''
return (Char c)
lexChar :: ReadP Char
lexCharE :: ReadP (Char, Bool) -- "escaped or not"?
lexCharE =
- do c <- get
- if c == '\\'
- then do c <- lexEsc; return (c, True)
- else do return (c, False)
+ do c1 <- get
+ if c1 == '\\'
+ then do c2 <- lexEsc; return (c2, True)
+ else do return (c1, False)
where
lexEsc =
lexEscChar
return (chr (fromInteger n))
lexCntrlChar =
- do char '^'
+ do _ <- char '^'
c <- get
case c of
'@' -> return '\^@'
lexString :: ReadP Lexeme
lexString =
- do char '"'
+ do _ <- char '"'
body id
where
body f =
+++ lexCharE
lexEmpty =
- do char '\\'
+ do _ <- char '\\'
c <- get
case c of
'&' -> do return ()
- _ | isSpace c -> do skipSpaces; char '\\'; return ()
+ _ | isSpace c -> do skipSpaces; _ <- char '\\'; return ()
_ -> do pfail
-- ---------------------------------------------------------------------------
lexHexOct :: ReadP Lexeme
lexHexOct
- = do char '0'
+ = do _ <- char '0'
base <- lexBaseChar
digits <- lexDigits base
return (Int (val (fromIntegral base) 0 digits))
lexFrac :: ReadP (Maybe Digits)
-- Read the fractional part; fail if it doesn't
-- start ".d" where d is a digit
-lexFrac = do char '.'
- frac <- lexDigits 10
- return (Just frac)
+lexFrac = do _ <- char '.'
+ fraction <- lexDigits 10
+ return (Just fraction)
lexExp :: ReadP (Maybe Integer)
-lexExp = do char 'e' +++ char 'E'
+lexExp = do _ <- char 'e' +++ char 'E'
exp <- signedExp +++ lexInteger 10
return (Just exp)
where
return xs
where
scan (c:cs) f = case valDig base c of
- Just n -> do get; scan cs (f.(n:))
+ Just n -> do _ <- get; scan cs (f.(n:))
Nothing -> do return (f [])
scan [] f = do return (f [])
val :: Num a => a -> a -> Digits -> a
-- val base y [d1,..,dn] = y ++ [d1,..,dn], as it were
-val base y [] = y
+val _ y [] = y
val base y (x:xs) = y' `seq` val base y' xs
where
y' = y * base + fromIntegral x
frac :: Integral a => a -> a -> a -> Digits -> Ratio a
-frac base a b [] = a % b
+frac _ a b [] = a % b
frac base a b (x:xs) = a' `seq` b' `seq` frac base a' b' xs
where
a' = a * base + fromIntegral x
| 'A' <= c && c <= 'F' = Just (ord c - ord 'A' + 10)
| otherwise = Nothing
+valDig _ _ = error "valDig: Bad base"
+
+valDecDig :: Char -> Maybe Int
valDecDig c
| '0' <= c && c <= '9' = Just (ord c - ord '0')
| otherwise = Nothing