Data.ByteString.Read

fractional

class (Fractional a, Num (Fraction a), Ord (Fraction a)) => ReadFractional a

Minimal complete definition

maxValue, fromFraction

Instances

ReadFractional Double

ReadFractional Float

ReadFractional Rational

fractional :: ReadFractional r => ByteString -> Maybe (r, ByteString)

convert bytestring into unsigned fractional using radix.

this function can parse

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

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

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

double = fractional

integral

integral :: Num n => ByteString -> Maybe (n, ByteString)

integral = integral' (Proxy :: Proxy 10)

int :: ByteString -> Maybe (Int, ByteString)

int = integral

common

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,"")

DEPRECATED

module Data.ByteString.Read.DEPRECATED