Proposal: Add split and splitWith (trac #2048)

[Twan van Laarhoven]

Don Stewart wrote:
> I'd like some QuickCheck properties, so we can avoid the unlines . lines /= id 
> fiasco. Given that, I'd support this too.

What is a good place to put those?

I just ran some obvious tests from ghci:

 > test (\x y -> intercalate [x::Int] (split x y) == y)
] OK, passed 100 tests.

 > test (\p xs -> all (not . any p) (splitWith p xs :: [[Int]]))
] OK, passed 100 tests.

for the unbeliever:
 > test (\x y -> splitWith (==x) y == split (x::Int) y)
] OK, passed 100 tests.

to show lazyness:
 > split 'a' $ concat $ repeat "abcdefgh"
] ["","bcdefgh","bcdefgh","bcdefgh",...

 > split 'z' $ concat $ repeat "abcdefgh"
] ["abcdefghabcdefghabcdefghabcdefgh...

Fiasco avoided :)

Twan