Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uunet!mcsun!hp4nl!solist!maestro!jand
From: jand@maestro.htsa.aha.nl (Jan Derriks)
Newsgroups: comp.lang.prolog
Subject: Re: What does/should your Prolog make of this ?
Keywords: cut assert fail backtracking
Message-ID: <1561@maestro.htsa.aha.nl>
Date: 8 Mar 90 14:31:45 GMT
References: <1990Mar1.210219.5687@Neon.Stanford.EDU> <1557@maestro.htsa.aha.nl> <1681@gould.doc.ic.ac.uk>
Sender: uucp@solist.htsa.aha.nl
Reply-To: jand@maestro.htsa.aha.nl (Jan Derriks)
Organization: AHA-TMF (Technical Institute), Amsterdam, The Netherlands
Lines: 21

In article <1681@gould.doc.ic.ac.uk> cdsm@doc.ic.ac.uk (Chris Moss) writes:
  >In article <1557@maestro.htsa.aha.nl> jand@maestro.htsa.aha.nl (Jan Derriks) 
  >>(1)   doo :- agenda(X), assertz(agenda(next)), write(X), fail.
  >
  >This is a standard problem with the semantics of assert and retract in Prolog
...
[using the 'static|transaction|logical' model]
  >Not all Prologs do this yet. But Quintus started and the Prolog standard has
  >also incorporated this notion, so hopefully more are following. Does anyone
  >know of others? Mail to me and I'll post.
As Roland Karlsson writes: SICStus prolog does.
  >I'm not convinced that either program should use assert or retract however.
  >
Can you tell that to rowe@cs.nps.navy.mil,
who wrote 'AI through Prolog' ? His book is full of this kind of stuff !.
(He used micro-prolog.)
-- 
Jan Derriks                  |       AHA-TMF (H.T.S. 'Amsterdam'),
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