Am 05.01.2012 11:57, schrieb Steve Horne:
[...]
groupCut :: (x -> x -> Bool) -> [x] -> [[x]]
[...]
How about a break function that respects an escape character (1. arg)
(and drops the delimiter - 2. arg) and use this function for unfolding?
import Data.List
break' :: (a -> Bool) -> (a -> Bool) -> [a] -> ([a], [a])
break' e p l = case l of
[] -> (l, [])
c : r
| p c -> ([], r)
| e c -> case r of
[] -> (l, [])
d : t -> let (f, s) = break' e p t in
(c : d : f, s)
| otherwise -> let (f, s) = break' e p r in
(c : f, s)
split' :: (a -> Bool) -> (a -> Bool) -> [a] -> [[a]]
split' e p = unfoldr $ \ l -> if null l then Nothing else
Just $ break' e p l
*Main> split' (== '\r') (== '\n') "string1\nstring2\r\nstring3\nstring4"
["string1","string2\r\nstring3","string4"]
C.
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