Proposal: Add chop function to Data.List

[Lennart Augustsson]

Yes, chop can be easily written in terms of unfoldr.  But the chop function
fits better with other existing list functions, like I tried to illustrate
with my examples.

  -- Lennart

On Tue, Dec 14, 2010 at 10:40 AM, Stefan Holdermans <
stefan at vectorfabrics.com> wrote:

> Henning,
>
> >> I would like to propose the following function for inclusion in
> Data.List
> >> chop :: (a -> (b, [a]) -> [a] -> [b]
> >> chop _ [] = []
> >> chop f as = b : chop f as'
> >>   where (b, as') = f as
>
>
> > Is the difference between 'unfoldr' and 'chop' just the Maybe result type
> of f?
>
>
> Yes.
>
>  chop f = unfoldr g
>    where
>      g [] = Nothing
>      g as = Just (f as)
>
> Cheers,
>
>  Stefan
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