Article View: comp.lang.prolog
Article #2622Re: Prolog control structures - (nf)
From: wagner
Date: Thu, 02 Apr 1987 08:42
Date: Thu, 02 Apr 1987 08:42
28 lines
1645 bytes
1645 bytes
/***** iaoobelix:comp.lang.pro / topaz!chomicki / 5:28 pm Mar 31, 1987*/
> In other words, xor(G1,G2) produces
> -- all and only solutions of G1 if one exists, XOR
> -- all and only solutions of G2 if one exists
...
> Jan Chomicki (chomicki@aramis.rutgers.edu) Phone: (201) 932-3999
> Dept.of Computer Science, Rutgers University, New Brunswick, NJ 08903
> Usenet: {...harvard,pyramid,seismo,nike}!rutgers!aramis!chomicki
> Arpanet: chomicki@aramis.rutgers.edu
The above `xor' predicate seems to be identical with something called
`default(X,Y)' (if I remember it right) available in Prolog-II. `default(X,Y)'
behaves like X if there is at least one solution for X, otherwise it behaves
like Y.
There are some other Prologs implementing this (e.g I saw one on the
Macintosh).
Juergen Wagner, USENET: ...seismo!unido!iaoobel!wagner
("Gandalf") or ...!pyramid!iaoobel!wagner
Mail: Juergen Wagner
Fraunhofer-Institut IAO
Rosenbergstr. 28
D-7000 Stuttgart 1
Federal Republic of Germany
Phone: + 49 711 6648-205
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Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: arc1-ca.pugleaf.net!utzoo!utgpu!water!watnot!watmath!clyde!rutgers!seismo!mcvax!unido!iaoobelix!wagner From: wagner@iaoobelix.UUCP Newsgroups: comp.lang.prolog Subject: Re: Prolog control structures - (nf) Message-ID: <7000007@iaoobelix.UUCP> Date: Thu, 2-Apr-87 03:42:00 EST Article-I.D.: iaoobeli.7000007 Posted: Thu Apr 2 03:42:00 1987 Date-Received: Sat, 4-Apr-87 19:07:42 EST References: <10588@topaz.UUCP> Lines: 28 Nf-ID: #R:topaz:10588:iaoobelix:7000007:000:1039 Nf-From: iaoobelix!wagner Apr 2 09:42:00 1987