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Date: -- (:)
From: David Brown <caml-list@d...>
Subject: Re: [Caml-list] Recursive lists
On Fri, Oct 08, 2004 at 04:42:44PM +0200, Alex Baretta wrote:
> Keith Wansbrough wrote:
> >
> >How could they do this?  It's just a list; there's nothing special
> >about it, except that it has no end.
> 
> Lists can be recursive. This means that the list type models a set of 
> values which includes the cyclic lists. The ocaml type system allow both 
> for such values and for functions manipulating them, so it's perfectly 
> natural to expect the List module to treat cyclic lists correctly. 
> Besides, the cyclicity of a list is a perfectly decidable property by 
> virtue of the pumping lemma.

I doubt that most users of list operations want the extra overhead needed
to check for cycles.  Recursive lists are fairly rare in strict languages.

Dave

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