[Haskell-cafe] Non Empty List?
miguelimo38 at yandex.ru
Thu Jun 4 17:55:52 EDT 2009
data Container a = Container a [a] ?
Or, maybe, you need something like zipper.
On 5 Jun 2009, at 01:53, Günther Schmidt wrote:
> I need to design a container data structure that by design cannot be
> empty and can hold n elements. Something like a non-empty list.
> I started with:
> data Container a = Single a | Many a [a]
> but the problem above is that the data structure would allow to
> construct a Many 5  :: Container Int.
> I can't figure out how to get this right. :(
> Please help.
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