Article View: comp.lang.functional
Article #186Re: pairs vs. triples
From: Andrew Koenig
Date: Fri, 28 Aug 1992 15:24
Date: Fri, 28 Aug 1992 15:24
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1560 bytes
In article <1992Aug26.141437.8465@swift.cs.tcd.ie> butrfeld@swift.cs.tcd.ie writes: > In a language called Sticks&Stones, based loosely on ML, that I have > used, the following equality always held: > (a,(b,c)) = (a,b,c) > In other words a triple is simply a pair whose second item is a pair. > Note that ((a,b),c) is not a triple. It sounds like that language didn't allow triples at all, only pairs. It's certainly possible to do that, but that would certainly be less convenient in other ways. For example, in ML a pair is a special case of a more general record type that consists of name-value pairs known and checked at compile time. A pair is just a record whose components are named 1 and 2; a triple is a record with components named 1, 2, and 3, and so on. I don't see how to allow pairs and not triples with that kind of unified design, and that unification is truly elegant and makes all sorts of other things easier to understand. -- --Andrew Koenig ark@europa.att.com
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arc1-ca.pugleaf.net!sparky!uunet!zephyr.ens.tek.com!uw-beaver!news.u.washington.edu!usenet.coe.montana.edu!uakari.primate.wisc.edu!zaphod.mps.ohio-state.edu!pacific.mps.ohio-state.edu!linac!att!att!dptg!ulysses!allegra!alice!arkReferences:
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Path: arc1-ca.pugleaf.net!sparky!uunet!zephyr.ens.tek.com!uw-beaver!news.u.washington.edu!usenet.coe.montana.edu!uakari.primate.wisc.edu!zaphod.mps.ohio-state.edu!pacific.mps.ohio-state.edu!linac!att!att!dptg!ulysses!allegra!alice!ark From: ark@alice.att.com (Andrew Koenig) Newsgroups: comp.lang.functional Subject: Re: pairs vs. triples Message-ID: <23577@alice.att.com> Date: 28 Aug 92 15:24:46 GMT References: <1992Aug26.141437.8465@swift.cs.tcd.ie> Reply-To: ark@alice.UUCP () Organization: AT&T Bell Laboratories, Murray Hill NJ Lines: 24