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[Caml-list] Why must types be always defined at the top level?
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Date: | 2004-06-25 (10:20) |
From: | skaller <skaller@u...> |
Subject: | RE: [Caml-list] Why must types be always defined at the top level? |
On Fri, 2004-06-25 at 05:46, John Hughes wrote: > Thanks for the answers. > > > 1. Why no eqtypes? > > > > Eqtypes have been hotly debated even among the SML designers. Hmm .. but interesting Ocaml has a slot to marshal abstract types .. and to finalise them .. but not to compare them. Bignums in particular don't work with polymorphic compare or hash, which means you can't for example use them as keys to a hashtable .. as I just discovered again :( Any thoughts on a way to fix that? My hashtable keys are terms which might contain integers which happen to be represented by big ints, so just using a custom hashtable won't work. In this case, I'd be more than happy to just hash the term's address (this would be heaps faster than the recursive polymorphic comparison) Is there a way to use an address as a comparable but otherwise opaque value? -- John Skaller, mailto:skaller@users.sf.net voice: 061-2-9660-0850, snail: PO BOX 401 Glebe NSW 2037 Australia Checkout the Felix programming language http://felix.sf.net ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners