[Haskell-cafe] Iteratee: manyToOne

[Felipe Almeida Lessa]

On Thu, Apr 28, 2011 at 12:09 PM, Felipe Almeida Lessa
<felipe.lessa at gmail.com> wrote:
> I foresee one problem: what is the leftover of 'manyToOne xs' if each
> x in xs needs different lengths of input?
>
> One possible untested-but-compiling solution:
[snip]

Like I said, that manyToOne implementation isn't very predictable
about leftovers.  But I guess that if all your iteratees consume the
same input OR if you don't care about leftovers, then it should be
okay.

*Main> E.run $ E.enumList 1 [5 :: Int, 6, 7] E.$$ manyToOne [return 1,
maybe 2 id `fmap` E.head, return 3, maybe 4 id `fmap` (E.head >>
E.head)] >>= \xs -> (,) xs `fmap` E.head
Right ([1,5,3,6],Just 7)
*Main> E.run $ E.enumList 10 [5 :: Int, 6, 7] E.$$ manyToOne [return
1, maybe 2 id `fmap` E.head, return 3, maybe 4 id `fmap` (E.head >>
E.head)] >>= \xs -> (,) xs `fmap` E.head
Right ([1,5,3,6],Just 6)

Cheers,

-- 
Felipe.