Data.ByteString.Read

functions

floating :: EffectiveDigit r => ByteString -> Maybe (r, ByteString)

convert bytestring into unsigned floating using radix.

this function can parse

• oct/hexa-decimal (0o,0O,0x,0X) (optional)
• floating(0.1, 12224.3543)
• exponential (e1, E+2, e-123) (10-radixed only, optional)

>>> floating "12.4" :: Maybe (Double, ByteString)
Just (12.4,"")
>>> floating "1.23e12" :: Maybe (Double, ByteString)
Just (1.23e12,"")
>>> floating "0o0.4" :: Maybe (Double, ByteString)
Just (0.5,"")
>>> floating "0x3f.12" :: Maybe (Double, ByteString)
Just (63.0703125,"")

double :: ByteString -> Maybe (Double, ByteString)

double = floating

signed :: Num r => (ByteString -> Maybe (r, ByteString)) -> ByteString -> Maybe (r, ByteString)

convert unsigned parser to signed parser.

this function can parse

• sign (+, -) (optional)

>>> signed double "12.4"
Just (12.4,"")
>>> signed double "-3.21e3"
Just (-3210.0,"")
>>> signed double "+0x1f.4"
Just (31.25,"")

classes

class (Fractional a, Num (Fraction a), Ord (Fraction a)) => EffectiveDigit a where

Associated Types

data Fraction a

data type to store fractional part of floating

Methods

maxValue :: proxy a -> Maybe (Fraction a)

maximum value of fractional part.

Nothing if arbitrary-precision.

Just $ fromIntegral (floatRadix t) ^ floatDigits t

fromFraction :: Num b => Fraction a -> b

lifted fromIntegral

Instances

EffectiveDigit Double

EffectiveDigit Float

EffectiveDigit Rational

class KnownNat n => Base n where

Methods

isDigit :: proxy n -> Word8 -> Bool

check input Word8 is digit charactor or not.

unsafeToDigit :: proxy n -> Word8 -> Word8

convert digit charactor to number. undefined behaviour when give non-digit charactor.

Instances

Base 2

Base 3

Base 4

Base 5

Base 6

Base 7

Base 8

Base 9

Base 10

Base 11

Base 12

Base 13

Base 14

Base 15

Base 16

Base 17

Base 18

Base 19

Base 20

Base 21

Base 22

Base 23

Base 24

Base 25

Base 26

Base 27

Base 28

Base 29

Base 30

Base 31

Base 32

Base 33

Base 34

Base 35

Base 36

raw functions

floating10 :: forall r. EffectiveDigit r => ByteString -> Maybe (r, ByteString)

convert bytestring into unsigned floating using radix.

this function can parse

• floating(0.1, 12224.3543)
• exponential (e1, E+2, e-123) (optional)

>>> floating10 "12.5" :: Maybe (Double, ByteString)
Just (12.5,"")
>>> floating10 "124.1e12" :: Maybe (Double, ByteString)
Just (1.241e14,"")
>>> floating10 "12.5e-3" :: Maybe (Double, ByteString)
Just (1.25e-2,"")
>>> floating10 "3.11e+3" :: Maybe (Double, ByteString)
Just (3110.0,"")

floating' :: (Base b, EffectiveDigit r) => proxy b -> ByteString -> Maybe (r, ByteString)

convert bytestring into unsigned floating using radix.

this function can parse

• floating(0.1, 12224.3543)

>>> floating' (Proxy :: Proxy 36) "12z" :: Maybe (Double, ByteString)
Just (1403.0,"")
>>> floating' (Proxy :: Proxy 2) "1012" :: Maybe (Double, ByteString)
Just (5.0,"2")
>>> floating' (Proxy :: Proxy 10) "a12" :: Maybe (Double, ByteString)
Nothing