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From: matsc@sics.se (Mats Carlsson)
Newsgroups: comp.lang.prolog
Subject: Re: Arrays in Prolog
Message-ID: <1990Sep11.150245.26833@sics.se>
Date: 11 Sep 90 15:02:45 GMT
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	<3899@bingvaxu.cc.binghamton.edu> <1990Aug28.065353.13951@sics.se>
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In-Reply-To: micha@ecrc.de's message of 3 Sep 90 12:03:51 GMT

In article <1032@ecrc.de> micha@ecrc.de (Micha Meier) writes:
   Value trailing is necessary to implement
   efficiently coroutining systems (yes, I know that it is possible
   without, but not fast enough). It was already present in MU-Prolog.

This is an interesting claim.  Could you provide some arguments for
why it is that coroutining systems become so much slower without value
trailing?  Value trailing seems to have a rather high price: the trail
becomes twice as large, and there is extra work for each (normal)
variable to reset.
--
Mats Carlsson
SICS, PO Box 1263, S-164 28  KISTA, Sweden    Internet: matsc@sics.se
Tel: +46 8 7521543      Ttx: 812 61 54 SICS S      Fax: +46 8 7517230