Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!bu-cs!purdue!i.cc.purdue.edu!j.cc.purdue.edu!pur-ee!uiucdcs!uxc.cso.uiuc.edu!uicsrd.csrd.uiuc.edu!sehr
From: sehr@uicsrd.csrd.uiuc.edu
Newsgroups: comp.lang.prolog
Subject: Call/1 and goal processing
Message-ID: <42200003@uicsrd.csrd.uiuc.edu>
Date: 7 Jun 88 02:31:00 GMT
Lines: 26
Nf-ID: #N:uicsrd.csrd.uiuc.edu:42200003:000:1003
Nf-From: uicsrd.csrd.uiuc.edu!sehr    Jun  6 21:31:00 1988



I am in the process of writing an Or-parallel interpreter for Prolog,
and have run across a difficulty.  The question I wonder about is how
other interpreters that use a structure-shared representation go about
implementing call/1 in an efficient manner without unduly penalizing
ordinary goal processing.  It seems that if one allows the interpretation
of dynamically constructed goals (i.e. those constructed via functor/3,
arg/3, and univ (=..)),  then one must cope with the possibility of
variable dereferencing during the selection of a goal to process.  Does
anyone out there know how it is done in other interpreters (C-Prolog,
SB-Prolog, etc.)?

David
-----
David C. Sehr
Center for Supercomputing Research and Development
University of Illinois at Urbana-Champaign
305 Talbot Lab
104 South Wright Street
Urbana, IL 61801-2932

Internet, BITNET:  sehr@uicsrd.csrd.uiuc.edu
UUCP:    {ihnp4,uunet,convex}!uiucuxc!uicsrd!sehr
ARPANET: sehr%uicsrd@uxc.cso.uiuc.edu
CSNET:   sehr%uicsrd@uiuc.csnet