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{-# LANGUAGE TypeSynonymInstances, FlexibleInstances #-}
module Text.Appar.Input where
import qualified Data.ByteString.Char8 as S
import qualified Data.ByteString.Lazy.Char8 as L
----------------------------------------------------------------
{-|
The class for parser input.
-}
class Eq inp => Input inp where
-- | The head function for input
car :: inp -> Char
-- | The tail function for input
cdr :: inp -> inp
-- | The end of input
nil :: inp
-- | The function to check the end of input
isNil :: inp -> Bool
instance Input S.ByteString where
car = S.head
cdr = S.tail
nil = S.empty
isNil = S.null
instance Input L.ByteString where
car = L.head
cdr = L.tail
nil = L.empty
isNil = L.null
instance Input String where
car = head
cdr = tail
isNil = null
nil = ""
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