{-# LANGUAGE OverloadedStrings, UnboxedTuples, CPP #-}
#if __GLASGOW_HASKELL__ >= 702
{-# LANGUAGE Trustworthy #-}
#endif
module Data.Text.Read
(
Reader
, decimal
, hexadecimal
, signed
, rational
, double
) where
import Control.Monad (liftM)
import Data.Char (isDigit, isHexDigit)
import Data.Int (Int8, Int16, Int32, Int64)
import Data.Ratio ((%))
import Data.Text as T
import Data.Text.Internal.Private (span_)
import Data.Text.Internal.Read
import Data.Word (Word, Word8, Word16, Word32, Word64)
type Reader a = IReader Text a
type Parser a = IParser Text a
decimal :: Integral a => Reader a
{-# SPECIALIZE decimal :: Reader Int #-}
{-# SPECIALIZE decimal :: Reader Int8 #-}
{-# SPECIALIZE decimal :: Reader Int16 #-}
{-# SPECIALIZE decimal :: Reader Int32 #-}
{-# SPECIALIZE decimal :: Reader Int64 #-}
{-# SPECIALIZE decimal :: Reader Integer #-}
{-# SPECIALIZE decimal :: Reader Word #-}
{-# SPECIALIZE decimal :: Reader Word8 #-}
{-# SPECIALIZE decimal :: Reader Word16 #-}
{-# SPECIALIZE decimal :: Reader Word32 #-}
{-# SPECIALIZE decimal :: Reader Word64 #-}
decimal txt
| T.null h = Left "input does not start with a digit"
| otherwise = Right (T.foldl' go 0 h, t)
where (# h,t #) = span_ isDigit txt
go n d = (n * 10 + fromIntegral (digitToInt d))
hexadecimal :: Integral a => Reader a
{-# SPECIALIZE hexadecimal :: Reader Int #-}
{-# SPECIALIZE hexadecimal :: Reader Int8 #-}
{-# SPECIALIZE hexadecimal :: Reader Int16 #-}
{-# SPECIALIZE hexadecimal :: Reader Int32 #-}
{-# SPECIALIZE hexadecimal :: Reader Int64 #-}
{-# SPECIALIZE hexadecimal :: Reader Integer #-}
{-# SPECIALIZE hexadecimal :: Reader Word #-}
{-# SPECIALIZE hexadecimal :: Reader Word8 #-}
{-# SPECIALIZE hexadecimal :: Reader Word16 #-}
{-# SPECIALIZE hexadecimal :: Reader Word32 #-}
{-# SPECIALIZE hexadecimal :: Reader Word64 #-}
hexadecimal txt
| h == "0x" || h == "0X" = hex t
| otherwise = hex txt
where (h,t) = T.splitAt 2 txt
hex :: Integral a => Reader a
{-# SPECIALIZE hex :: Reader Int #-}
{-# SPECIALIZE hex :: Reader Int8 #-}
{-# SPECIALIZE hex :: Reader Int16 #-}
{-# SPECIALIZE hex :: Reader Int32 #-}
{-# SPECIALIZE hex :: Reader Int64 #-}
{-# SPECIALIZE hex :: Reader Integer #-}
{-# SPECIALIZE hex :: Reader Word #-}
{-# SPECIALIZE hex :: Reader Word8 #-}
{-# SPECIALIZE hex :: Reader Word16 #-}
{-# SPECIALIZE hex :: Reader Word32 #-}
{-# SPECIALIZE hex :: Reader Word64 #-}
hex txt
| T.null h = Left "input does not start with a hexadecimal digit"
| otherwise = Right (T.foldl' go 0 h, t)
where (# h,t #) = span_ isHexDigit txt
go n d = (n * 16 + fromIntegral (hexDigitToInt d))
signed :: Num a => Reader a -> Reader a
{-# INLINE signed #-}
signed f = runP (signa (P f))
rational :: Fractional a => Reader a
{-# SPECIALIZE rational :: Reader Double #-}
rational = floaty $ \real frac fracDenom -> fromRational $
real % 1 + frac % fracDenom
double :: Reader Double
double = floaty $ \real frac fracDenom ->
fromIntegral real +
fromIntegral frac / fromIntegral fracDenom
signa :: Num a => Parser a -> Parser a
{-# SPECIALIZE signa :: Parser Int -> Parser Int #-}
{-# SPECIALIZE signa :: Parser Int8 -> Parser Int8 #-}
{-# SPECIALIZE signa :: Parser Int16 -> Parser Int16 #-}
{-# SPECIALIZE signa :: Parser Int32 -> Parser Int32 #-}
{-# SPECIALIZE signa :: Parser Int64 -> Parser Int64 #-}
{-# SPECIALIZE signa :: Parser Integer -> Parser Integer #-}
signa p = do
sign <- perhaps '+' $ char (\c -> c == '-' || c == '+')
if sign == '+' then p else negate `liftM` p
char :: (Char -> Bool) -> Parser Char
char p = P $ \t -> case T.uncons t of
Just (c,t') | p c -> Right (c,t')
_ -> Left "character does not match"
floaty :: Fractional a => (Integer -> Integer -> Integer -> a) -> Reader a
{-# INLINE floaty #-}
floaty f = runP $ do
sign <- perhaps '+' $ char (\c -> c == '-' || c == '+')
real <- P decimal
T fraction fracDigits <- perhaps (T 0 0) $ do
_ <- char (=='.')
digits <- P $ \t -> Right (T.length $ T.takeWhile isDigit t, t)
n <- P decimal
return $ T n digits
let e c = c == 'e' || c == 'E'
power <- perhaps 0 (char e >> signa (P decimal) :: Parser Int)
let n = if fracDigits == 0
then if power == 0
then fromIntegral real
else fromIntegral real * (10 ^^ power)
else if power == 0
then f real fraction (10 ^ fracDigits)
else f real fraction (10 ^ fracDigits) * (10 ^^ power)
return $! if sign == '+'
then n
else -n