On Sat, 2009-01-17 at 21:55 +0100, Jean-Philippe Bernardy wrote:
> I think it should admit empty, and the traversable instance should
> traverse the first list in reverse.
I fixed the latter issue so that the behavior is correct (I think).
I tested it like this:
> forM (next $ next $ fromList [1..5]) $ \i -> do { print i; return i }
1
2
3
4
5
[1,2] 3 [4,5]
which I believe is proper.
I'm undecided about allowing them to be empty. I don't know the theory
or math behind zippers (I'm sure there are some papers written about
it), but it doesn't make much sense to be empty. I got that impression
from #haskell, also.
Thanks for the comments. :)
Jeff Wheeler
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