Meeting Pearls 1/Meeting Pearls Vol 1 (1994).iso/installed_progs/text/faqs/prolog.resource-guide.part1

Internet Message Format | 1994-05-15 | 58.3 KB

Subject: FAQ: Prolog Resource Guide 1/2 [Monthly posting]
Newsgroups: comp.lang.prolog,comp.object.logic,news.answers,comp.answers
From: [e-mail] (Mark Kantrowitz)
Date: Fri, 13 May 1994 14:53:20 GMT

Archive-name: prolog/resource-guide/part1
Last-Modified: Wed Apr 20 01:23:33 1994 by Mark Kantrowitz
Version: 1.18

;;; ****************************************************************
;;; Prolog Resource Guide ******************************************
;;; ****************************************************************
;;; prg_1.faq -- 57569 bytes

Contributions, corrections, suggestions, and comments should be sent
to Mark Kantrowitz at [e-mail].

This guide lists a variety of resources for the Prolog community,
including books, magazines, ftp archives, and products. It is posted
once a month to the newsgroups comp.lang.prolog and comp.object.logic.

*** Copyright:

Copyright (c) 1992-94 by Mark Kantrowitz. All rights reserved.

This FAQ may be freely redistributed in its entirety without
modification provided that this copyright notice is not removed.  It
may not be sold for profit or incorporated in commercial documents
(e.g., published for sale on CD-ROM, floppy disks, books, magazines,
or other print form) without the prior written permission of the
copyright holder.  Permission is expressly granted for this document
to be made available for file transfer from installations offering
unrestricted anonymous file transfer on the Internet.

This article is provided AS IS without any express or implied warranty.

*** Acknowledgments:

The original version of this guide (Version 0.6, Dec 11, 1991) was
compiled by Dag Wahlberg, Uppsala University, Sweden <[e-mail]>.
Other people who helped with the compilation include Chris Moss
<[e-mail]>, Mats Carlsson, SICS <[e-mail]>,
Michael A. Covington <[e-mail]>, Jocelyn Paine
<[e-mail]>, Per G. Bilse, PDC <[e-mail]>, David Cohen, BIM
Systems Inc <[e-mail]>, Mark Korsloot <[e-mail]>, and
David W. Talmage <[e-mail]>.

Thanks also to Jamie Andrews <[e-mail]>.

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Table of Contents (Part 1):
  [1-0]  Introduction
  [1-1]  Sources of information about Prolog
  [1-2]  FTP Archives and Other Resources
  [1-3]  Free Object-Oriented Systems for Prolog
  [1-4]  Commercial Object-Oriented Systems for Prolog
  [1-5]  The Prolog 1000 Database
  [1-6]  X-Windows Interfaces
  [1-7]  Prolog-related Mailing Lists
  [1-8]  Books and Magazine Articles
  [1-9]  Is there a straight-forward way of compiling Prolog to C?
  [1-10] WAM emulators and tracers
  [1-11] What is the Basic Andorra Model and AKL?
  [1-12] What is Constraint Logic Programming?
  [1-13] How do you write portable programs in Prolog?

Prolog Implementations (Part 2):
  [2-0]  General information about Prolog Implementations
  [2-1]  Free Prolog Implementations
  [2-2]  Commercial Prolog Implementations
  [2-3]  Free Parallel Prolog Implementations
  [2-4]  Commercial Parallel Prolog Implementations
  [2-5]  Free Constraint Systems
  [2-6]  Commercial Constraint Systems
  [2-7]  Free Logic Programming Systems
  [2-8]  Commercial Logic Programming Systems

Search for [#] to get to topic number # quickly. In newsreaders which
support digests (such as rn), [CTRL]-G will page through the answers.


Recent Changes:
;;; 1.18:
;;; 20-APR-94 mk    Added IBM SAA AD/Cycle Prolog to [2-2] and ICE (Integrated
;;;                 Constraint Engine) to [2-6].
;;; 22-APR-94 mk    Updated ftp information for ftp.gmd.de.
;;; 22-APR-94 mk    New edition of Sterling's book.
;;;  9-MAY-94 mk    Updated Arity email addresses.
;;; 12-MAY-94 mk    Added citation for the Goedel book to the Goedel entry.
;;; 12-MAY-94 mk    Added Koen De Bosschere's prolog parser (C) to [1-2].
;;; 12-MAY-94 mk    Added entry on Flach's Prolog book.
;;; 12-MAY-94 mk    Added entry on Karlsson's collection of Queens and Knights
;;;                 implementations.

----------------------------------------------------------------
Subject: [1-0] Introduction

This guide lists Prolog resources: archives, newsgroups, books,
magazines, compilers, interpreters and anything else you can think of
which has to do with the proliferation of Prolog. Also included is a
list of suppliers of products and a list of publishers. As Prolog has
a strong historical tradition in Europe, we've tried to ensure that
the information is relevant to all readers, including European and
North American.

This guide is posted regularly to comp.lang.prolog and comp.object.logic.
It may also be obtained by anonymous ftp from
   ftp.cs.cmu.edu:/user/ai/pubs/faqs/prolog/  [128.2.206.173]
using username "anonymous" and password "name@host" (substitute your
email address) or via AFS in the Andrew File System directory
   /afs/cs.cmu.edu/project/ai-repository/ai/pubs/faqs/prolog/
as the files prg_1.faq and prg_2.faq.

You can also obtain a copy of the FAQ by sending a message to
[e-mail] with
   Send PRG
in the message body.

The FAQ postings are also archived in the periodic posting archive on
   rtfm.mit.edu:/pub/usenet/news.answers/prolog/ [18.70.0.209]
If you do not have anonymous ftp access, you can access the archive by
mail server as well.  Send an E-mail message to
[e-mail] with "help" and "index" in the body on
separate lines for more information.

An automatically generated HTML version of the PRG is accessible by
WWW as part of the AI-related FAQs Mosaic page. The URL for this
resource is
   http://www.cs.cmu.edu:8001/Web/Groups/AI/html/faqs/top.html
The direct URL for the PRG is
   http://www.cs.cmu.edu:8001/Web/Groups/AI/html/faqs/lang/prolog/prg/top.html

If you need to cite the FAQ for some reason, use the following format:
   Mark Kantrowitz, "Prolog Resource Guide", comp.lang.prolog, <month>, <year>,
   ftp.cs.cmu.edu:/user/ai/pubs/faqs/prolog/prg_?.faq, [e-mail].

Disclaimer:

   We have taken great care in making the information in this document as
   accurate as possible. However we are not responsible for any problems
   which might occur from using information supplied in this guide.

----------------------------------------------------------------
Subject:  [1-1]  Sources of Information about Prolog

The newsgroups comp.lang.prolog, comp.object.logic, and (to a lesser
extent) comp.ai are a source of information and discussion about Prolog.
See also sci.logic. The newsgroup comp.constraints is for information
about constraint processing languages and related topics.

A "Frequently Asked Questions" posting is posted to comp.lang.prolog
twice a month by Jamie Andrews <[e-mail]>. The Prolog FAQ and this
Prolog Resource Guide are intended to complement one another.

The draft ISO standard for Prolog is available by anonymous ftp from
ai.uga.edu:/pub/prolog.standard/ [128.192.12.9]. An unofficial summary
of the draft ISO Prolog standard is available from the same location
as isoprolog.tex or isoprolog.ps.Z.  Send mail to Michael Covington
<[e-mail]> for more information.

----------------------------------------------------------------
Subject: [1-2] FTP Archives and Other Resources

The following are achives that contain Prolog-related material, such as
code, interpreters, articles, etc. Most of the archives are ftp sites.
They are listed by domain.name and [IP Address]. To access them and
download programs type at the prompt:

        ftp <site name> (or IP address)
        login: "anonymous",
        password: your own return email address,
        cd <directory>, ls to see files,
        set binary,
        get <filename> to transfer file to your system
        stop with quit or exit

Deviations from this general scheme may occur but the above should
work in most cases.


Artificial Intelligence Programs:
   ai.uga.edu:/pub/ [128.192.12.9]

   The University of Georgia AI FTP Library contains public domain
   Prologs, such as Open Prolog and ESL PD Prolog, PrEd (a small text
   editor for Prolog), and some miscellaneous prolog programs in
      ai.uga.edu:/pub/prolog/
   A copy of the programs from the book by Covington, Nute, and Vellino, (see
   the section on Books below), is in
      ai.uga.edu:/pub/prolog.book/
   and the draft ISO standard for prolog is in
      ai.uga.edu:/pub/prolog.standard/
   Some technical reports with accompanying code are in
      ai.uga.edu:/pub/ai.reports/
   Other materials of interest are in
      ai.uga.edu:/pub/natural.language/
      ai.uga.edu:/pub/natural.language.book/
   Maintained by Michael Covington <[e-mail]>.

ALE:
   ALE (Attribute Logic Engine), a public domain system written in
   Prolog, integrates phrase structure parsing and constraint logic
   programming with typed feature structures as terms.  Types are
   arranged in an inheritance hierarchy and specified for the features
   and value types for which they are appropriate.  Grammars may also
   interleave unification steps with logic program goal calls (as can be
   done in DCGs), thus allowing parsing to be interleaved with other
   system components.  While ALE was developed to handle HPSG grammars,
   it can also execute PATR-II grammars, DCG grammars, Prolog, Prolog-II,
   and LOGIN programs, etc. Grammars and programs are specified with a
   version of Rounds-Kasper Attribute Value Logic with macros and
   variables.  ALE supports lexical rules and empty categories for
   grammars, using a bottom-up, breadth-first dynamic chart parser. ALE
   supports last call optimization, negation by failure and cuts in
   definite clauses, which may be used independently or integrated into
   grammars. The system is available free for research purposes, from
   Bob Carpenter <[e-mail]>.

ALP-UK Library:
   The best Prolog library currently is the one collected by the ALP-UK
   group. It is available to members at 30 pounds sterling for a Sun
   cartridge or 2 pounds/IBM DOS disk. (non-members maybe, how much?) It
   contains MBs of Prolog systems (including SB Prolog), libraries
   (including the Edinburgh library), benchmarks, grammars, theorem provers,
   object and graphics systems etc. For more information, write to ALP-UK
   Library, Sanjay Raina, Librarian, Dept. of Computer Science, University
   of Bristol, University Walk, Bristol BS8 1TR, UK, call [phone]
   x3304, or send email to [e-mail].

CASLOG
   CASLOG (Complexity Analysis System for LOGic) is an experimental
   semi-automatic complexity analysis system for logic programs. It can
   perform the worst-case analysis for complexity measures: argument size
   complexity, number of solutions complexity, and time complexity.

   CASLOG extends the techniques developed for analyzing imperative and
   functional languages to deal with nondeterminism and generation of
   multiple solutions via backtracking in logic languages. The analyses
   for different complexity measures are implemented in a unified
   framework and share several common features. First, the predicates in
   a program are processed in an order generated by a bottom-up
   topological sorting over the call graph of the program. Second, the
   complexity function for a predicate is derived from the complexity
   function of its clauses by using the information about the mutual
   exclusion relationships between its clauses. Third, the complexity
   function for a clause is inferred based on the data dependency
   relationships between its literals. Fourth, the complexity functions
   for recursive clauses are in the form of difference equations and are
   transformed into closed form functions using difference equation
   solving techniques. This unified framework can simplify proofs of
   correctness and the implementation of the algorithms.

   CASLOG is available by anonymous ftp from cs.arizona.edu:/caslog/. This
   is an alpha distribution, and includes CASLOG version 1.0, a
   preliminary user manual, a paper on CASLOG, and a set of examples.
   For more information, contact Nai-Wei Lin <[e-mail]>.

Constraint Programming Paper Archive:
   Aarhus University, Denmark, has established an anonymous ftp archive
   for papers on "Constraint Programming" at ftp.daimi.aau.dk:/pub/CLP/.
   For further information, contact Brian H. Mayoh <[e-mail]>.

CSP:

   Some constraint-related papers by a research group at the
   University of Washington are available by anonymous ftp from
      june.cs.washington.edu:/pub/constraints/papers/
   The papers from the 1994 Principles and Practice of Constraint
   Programming Workshop are available in
      june.cs.washington.edu:/pub/constraints/papers/ppcp94/
   There are also implementations of several constraint satisfaction
   algorithms and constraint-based systems, including the DeltaBlue and
   SkyBlue algorithms, the Multi-Garnet user interface toolkit, ThingLab
   II, and CoolDraw (a constraint-based drawing system), in
   subdirectories of
      june.cs.washington.edu:/pub/constraints/code/
   The ftp archive is also accessible via WWW:
      http://web.cs.city.ac.uk/archive/constraints/constraints.html
   All the source code is in the public domain. For more information,
   write to Alan Borning <[e-mail]>.

   C implementations of a number of constraint satisfaction algorithms
   are available by anonymous ftp from
      ftp.cs.ualberta.ca:/pub/ai/csp/
   Get the files README and csplib.tar.Z.  The algorithms include
   variations on backtracking (backjumping, backmarking, chronological
   backtracking, etc.), local consistency preprocessing algorithms (e.g.,
   arc consistency), and random problem generators. For more information,
   write to Peter van Beek <[e-mail]>.

Eden:
   Eden is a Poplog-based AI microworld developed by Simon Perkins,
   Jocelyn Paine and Edmund Chattoe of the Oxford University Artificial
   Intelligence Society. It is intended to serve as a testbed for
   learning and planning programs. Programs written in Pop-11, Prolog,
   Lisp, and ML control a "bug" that lives in a 2-dimensional world. Any
   kind of algorithm may be used to control the bug, including genetic
   algorithms, neural nets, and rule-based systems. Eden consists of a
   grid of cells, each of which can contain objects such as keys, doors,
   boulders and quicksand. Bug's objective is to find and eat a piece of
   food which the simulator has placed somewhere within this grid. To do
   this, Bug must negotiate its way towards the food while dealing
   intelligently with obstacles. Eden's laws of physics allow Bug to take
   one of several different actions when it encounters an object. The
   simulator then works out the consequences of the chosen action on Bug
   and on Eden, and displays these graphically in a Ved window. Bug's
   perceptions are updated to reflect the new state of the world, and the
   cycle repeats. Eden is available by anonymous ftp from the Imperial
   College archive in
      src.doc.ic.ac.uk:/packages/prolog-pd-software/ [146.169.2.10]
   as the file eden.tar.Z. (Note: This is really a link to the
   directory computing/programming/languages/prolog/pd-software/.)
   Eden includes PopBeast, a simple Prolog bug which can read and
   parse simple commands, extract their meaning, plan how to satisfy
   these commands, and then carry out the plans.

   Parts of the current Eden are coded in Pop-11, so porting it to
   Prologs other than Poplog will require some effort. Most of the
   recoding needed is in the grid-world simulator and the definition of
   objects. Send mail to Jocelyn Paine <[e-mail]> if
   you're willing to try this.

Logic Programming Bibliographies:
   duck.dfki.uni-sb.de:/pub/lp-proceedings/ [134.96.188.92]

   The ftp server supports tar'ing on the fly, so if you type "get
   bibtex.tar" you will get a tar'ed version of the "bibtex" directory.

   BibTeX entries for the proceedings of the following conferences
   are included: SLP84-87,91, NACLP89-90, ILPS91, ICLP82,84,86-91,93,
      JICLP92, LP88, RTA89,93, PLILP90-92, ALPUK91, ICOT92, ALP90,92,
      CADE90,92, CTRS90,92, LICS86-91, UNIF89, EPIA89,91,93, TACS91,
      TAPSOFT93, EAIA90, FGCS92, FAC, ILPS93
   and the following journals: JLP85-93, JAR91,92, JSC91,92, IANDC82-92.

   The bibliography is mirrored by the Universidade Nova de Lisboa.
   In addition, the bibliography can be searched using either WAIS or
   GOPHER. To search the lp-proceedings using WAIS, use the
      lp-proceedings.src
   wais source, available from the directory of servers. To search the
   lp-proceedings using GOPHER, point the client to gopher.fct.unl.pt,
   and follow the directories
      "Research/Bibliography/Logic Programming Proceedings".
   Searching should be easier than retrieving the entire package every
   time you want to locate a particular article.

   Send comments and bug reports to [e-mail].

Machine Learning Algorithms Implemented in Prolog:

   In 1988 the Special Interest Group on Machine Learning of the German
   Society for Computer Science (GI e.V.) decided to establish a library
   of PROLOG implementations of Machine Learning algorithms. The library
   includes - amongst others - PROLOG implementations of Winston's arch,
   Becker's AQ-PROLOG, Fisher's COBWEB, Brazdil's generation of
   discriminations from derivation trees, Quinlan's ID3, inverse
   resolution, and Mitchell's version spaces algorithm. The programs are
   currently available via anonymous ftp-server from the GMD:

        ftp.gmd.de:/gmd/mlt/ML-Program-Library [129.26.8.84]

   Send additional PROLOG implementations of Machine Learning
   Algorithms, complaints about them and detected bugs or problems
   to Thomas Hoppe, <[e-mail]>. Send suggestions and
   complaints about the ftp library to Werner Emde, Gesellschaft
   fuer Mathematik und Datenverarbeitung, Bonn, <[e-mail]>.


Natural Language Processing in Prolog:

   The Prolog and DCG programs from Pereira and Shieber's book, "Prolog
   and Natural Language Analysis", are available by anonymous ftp from
   das.harvard.edu:/pub/shieber/pnla/. See the file README for the
   conditions under which the material is distributed. If you retrieve
   the files, please send an email message to the authors letting them
   know how you plan to use them. For further information, write to
   Fernando Pereira <[e-mail]> or Stuart Shieber
   <[e-mail]>.

Parser:
   A parser for standard Prolog text written in C is available by
   anonymous ftp from
      trappist.elis.rug.ac.be:/pub/prolog/
   It consists of only three modules (tokenizer, parser, and display
   routine) and an interface module to integrate it with an existing
   Prolog system. It is completely deterministic and about 10 times
   faster than O'Keefe's public domain parser written in Prolog.
   For more information, write to Koen De Bosschere <[e-mail]>.

Pleuk Grammar Development System:

   Pleuk is intended to be a shell for grammar development, in that many
   different grammatical formalisms can be embedded within it.
   Grammatical formalisms that currently work with Pleuk include CFG (a
   simple context-free grammar system), HPSG-PL (a system for developing
   HPSG-style grammars, produced at Simon Fraser University, Canada, by
   Fred Popowich, Sandi Kodric and Carl Vogel), Mike (a simple
   graph-based unification system, enhanced with additional operations
   for the treatment of free word order proposed by Mike Reape in various
   publications), SLE (a graph-based formalism enhanced with arbitrary
   relations in the manner of Johnson & Rosner and Doerre & Eisele.
   Delayed evaluation is used to compute infinite relations.  This system
   has been used for the development of several HPSG-style grammars) and
   Term (a term-based unification grammar system, originally developed
   for the support of Unification Categorial Grammar of Zeevat, Klein and
   Calder). Sample grammars are provided for all of these formalisms.
   Work continues apace on other formalisms, including Bob Carpenter's
   Ale system for typed feature structures, and Veronica Dahl's Static
   Discontinuity Grammars.

   Pleuk requires SICStus prolog version 2.1#6 or later, plus a variety
   of ancillary programs available free of charge from many FTP servers.
   Pleuk is available via anonymous FTP from the University of Georgia
   Artificial Intelligence FTP library
      ai.uga.edu:/pub/natural.language/
   as the files pleuk.1.0.tar.Z, pleuk.PSmanuals.tar.Z, and pleuk.README.
   Pleuk will also be available shortly from the Natural Language
   Software Registry, German Research Institute for Artificial
   Intelligence (DKFI), Saarbruecken.  For more information, send email
   to [e-mail].

Prolog Repository:
   Established by Jocelyn Paine of Experimental Psychology, Oxford
   University in 1987. The current catalogue (January 1991) contains
   30 entries. For catalogue, queries and contributions contact POPX at:
      [e-mail] (internet) or
      [e-mail] (janet)

   FTP access is available through the Imperial College archive at
      src.doc.ic.ac.uk:/packages/prolog-pd-software/  [146.169.2.10]
   This is actually a link to the directory
      /computing/programming/languages/prolog/pd-software/

   To access it, cd to either of the above directories via
   anonymous ftp. The file README gives a brief summary of the
   contents of the directory and CATALOGUE gives a (long!)
   description of each entry. Entries include the Logic Programming
   Tutor from Paine's book, the DEC-10 public-domain library, the
   Linger natural-language corrector, a simple object-oriented
   add-on for Prolog, graph utilities, among other things.

   Files in the archive are also available on MS-DOS floppies for a
   nominal fee to cover the cost of floppies, postage, and packing.

Prolog to SQL Compiler:
   The Prolog to SQL Compiler translates database access requests,
   which consist of a projection term and a database goal, to the
   appropriate SQL query. The compiler is written in standard Edinburgh
   Prolog and has been ported to a number of Prologs. The code posted to
   comp.lang.prolog works in ECRC's SEPIA Prolog, but should be easily
   ported to other Prologs. A detailed tech report on the implementation
   is available by email from [e-mail] (include
   your full postal address). The compiler is copyright, but may be used
   free of charge for non-commercial purposes and redistributed provided
   the copyright notice is retained intact.

PSI:
   PSI is a handy system for the management and retrieval of your
   personal data, be it addresses, CD collections, or bibliographic
   references. It is intended for the non-commercial user. It may not be
   as full-fledged as some data-base systems, but has some features that
   you won't find in most commercial systems. Also, you may find it
   easier to set up and faster to use. PSI is useful for a broad range of
   data. Indexing with descriptors makes searching for the data you need
   fast, and the interface to other data-base formats (import and export)
   is quite powerful. PSI was written in LPA MacProlog and is a "genuine
   'double clickable' Mac application". PSI runs on all Macs with System
   6 or 7 in 1MB of main memory. As LPA MacProlog isn't yet 32-bit clean,
   PSI isn't either. Extensive documentation and some examples are
   included. PSI is available by anonymous ftp from
   sumex-aim.stanford.edu:/info-mac/app/ as the file psi-23.hqx. It
   was also available on a recent Nautilus CD-ROM and will be on the
   first Info-Mac CD-ROM.

Queens and Knights:
   Queens and Knights are favorite problems for Prolog programmers.
   A collection of several implementations is available by anonymous
   ftp from sics.se:/pub/muse/queensANDknights.tar.Z.uue
   Write to Roland Karlsson <[e-mail]> for more information.

Rubik's Cube:
   Amzi!, the creators of Cogent Prolog, have made sources to Cube Solver
   II available from their ftp site, ftp.std.com:/vendors/amzi/.  It is
   also available from the Prolog Repository at CMU, in
   ftp.cs.cmu.edu:/user/ai/lang/prolog/code/fun/rubik/.  This Prolog
   program solves Rubik's Cube.  The sources include a simple scrolling
   interface that should work in any Edinburgh standard Prolog.  Also
   included is a ready-made executable for 386 and 486 PCs; it was
   implemented using Cogent Prolog.  For more information, write to Amzi!
   Inc. (formerly Amziod) <[e-mail]>, 40 Samuel Prescott Dr.,
   Stow, MA 01775, Tel: [phone]. Fax: [phone].

SEL:
   SEL is a declarative set processing language. Its main features are
   subset and equational program clauses, pattern matching over sets,
   support for efficient iteration and point-wise/incremental computation
   over sets, the ability to define transitive closures through circular
   constraints, meta-programming and simple higher-order programming, and
   a modest user-interface including tracing. The language seems
   well-suited to a number of problems in graph theory, program analysis,
   and discrete mathematics. The SEL compiler is written in Quintus
   Prolog and the run-time system is written in C. It generates WAM-like
   code, extended to deal with set-matching, memoization, and the novel
   control structure of the language. SEL is available by anonymous FTP
   from ftp.cs.buffalo.edu:/users/bharat/SEL2/.  The FTP release comes with a
   user manual, bibliography of papers (including .dvi files), several
   sample programs, and source code. For further information, write to
   Bharat Jayaraman <[e-mail]>.

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Subject: [1-3] Free Object-Oriented Systems for Prolog

OL(P), Object Layer for Prolog, is an object-oriented extension to
Prolog.  It provides an object-oriented structuring and reuse
mechanism for Prolog in a manner that preserves performance and
semantics. The object-oriented layer is compiled into Prolog without
introducing any side-effects.  OL(P) takes the view of objects as
collections of predicates (called methods).  To Prolog, OL(P) 1.1 adds
objects with methods, data encapsulation, instances, and multiple
inheritance. Object methods can access Prolog predicates and vice
versa. The OL(P) incremental compiler translates OL(P) programs to
Prolog programs that don't need runtime interpretation (e.g., no
search is needed for inheritance).  OL(P) 1.1 comes with prepared
installation for SICStus Prolog and QUINTUS Prolog (both on UNIX),
documentation, simple built-in project management, some libraries,
and example programs. The source is included, so you can port OL(P)
to different platforms, different Prolog systems, and different
logic programming languages. OL(P) is available by anonymous ftp
from parcftp.xerox.com:/ftp/pub/ol/ [13.1.64.94]. Written by Markus
P.J. Fromherz <[e-mail]>.

See Common ESP (CESP) in [2-1] and BeBOP in [2-3].

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Subject: [1-4] Commercial Object-Oriented Systems for Prolog

LAP is an object-oriented system by Elsa. For more information, write
to Elsa Software, La Grange Dame Rose, 6 ave du Marechal Juin, 92366
Meudon-La-Foret Cedex, France, call [phone], fax +33 (1)
46 30 55 26, or send email to elsa![e-mail].

SPIRAL is an object oriented system by CRIL for Sun3 and Sun4 under
Unix. For more information, write to CRIL, Conception et Realisation,
Industriel de Logiciel, 146 bd de Valmy 92707, Colombes Cedex, France,
call [phone], or fax [phone].

See also LPA Prolog ++ in [2-2].

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Subject: [1-5]  The Prolog 1000 Database

The Prolog 1000 is a database of real Prolog applications being
assembled in conjunction with the Association for Logic Programming
(ALP) and PVG. The aim is to demonstrate how Prolog is being used in
the real world and it already contains over 500 programs with well
over 2 million lines of code. The database is available for research
use in SGML format from the Imperial College archive
   src.doc.ic.ac.uk:/packages/prolog-progs-db/prolog1000.v1.gz
If you have or know about a program that might qualify for inclusion,
send an email message to Al Roth ([e-mail]) for an
electronic entry form which only takes a few minutes to complete. Or
write to Prolog 1000, PO Box 137, Blackpool, Lancashire, FY2 0XY,
U.K., Fax: [phone] Telephone: [phone]. (Floppy disks for
PC or Mac in text form are also welcome, and paper entries may also be
sent). Queries may also be addressed to: Chris Moss
([e-mail]), Leon Sterling ([e-mail]).

----------------------------------------------------------------
Subject: [1-6] X-Windows Interfaces

PI:
   PI is an interface between Prolog applications and the X Window System
   that aims to be independent from the Prolog engine, provided that it
   has a Quintus-style foreign function interface (such as SICStus, YAP).
   It is mostly written in Prolog and is divided in two libraries: (1)
   Edipo, a low-level interface to the Xlib functions, and (2) Ytoolkit,
   a high-level user interface toolkit that allows you to create and
   manage graphical objects, define new classes of objects, and handle
   user interaction. PI is available by anonymous ftp from
   ftp.ncc.up.pt:/pub/prolog/pi_1.2.tar.gz and includes documentation
   and some demos. Also see ytoolkit.tar.Z. PI has been tested in
   Quintus Prolog 3.1.1 and SICStus 2.1 #8. Send questions, comments,
   and bug reports to Ze' Paulo Leal, Universidade de Porto, Portugal,
   <[e-mail]>.

XWIP:
   ftp.x.org:/contrib/xwip.tar.Z  (formerly export.lcs.mit.edu)
   ftp.uu.net:/X/contrib/xwip.tar.Z

   XWIP is an X Windows interface for PROLOG.

XPCE:
   XPCE is an object-oriented X-window interface toolkit for symbolic
   programming languages (Prolog and Lisp), offering a high level of
   abstraction for communication with X11, Unix processes, Unix
   networking facilities (sockets) and Unix files. XPCE's built-in
   classes (about 150) are mostly written in C.  The XPCE/Prolog
   interface allows the user to create and manipulate instances of these
   classes.  The user can also create new XPCE classes from Prolog.
   XPCE's window related classes provide various styles of menus,
   primitive graphical objects, compound graphical objects and Emacs
   oriented programmable text manipulation windows. The distribution
   contains several demo programs, including a diagram drawing tool
   (PceDraw), an animation demo, an Epoch-like editor, a graphical
   interface to Unix ispell, and an online hyper-text manual for XPCE
   itself.  A demo version of XPCE/SWI-Prolog for Linux may be obtained
   by anonymous ftp from swi.psy.uva.nl:/pub/xpce/linux/ [145.18.114.17].
   The non-demo versions (for SWI-Prolog, SICStus Prolog, Lucid Common
   Lisp and LispWorks) require filling out a license and paying a fee
   (see the file pub/xpce/INFO).  To be added to the mailing list
   [e-mail] send mail to [e-mail]. Send
   bugs to [e-mail].

   ProWindows 3 is a commercial version of XPCE for Quintus Prolog.
   For further information, write to Simon Heywood, AI International Ltd,
   The Chapel, Park View House, 1 Park View Road, Berkhamsted, Herts,
   HP4 3EY, phone [phone] (Sales Hotline [phone]),
   fax [phone], or send email to [e-mail].

ProTcl:
   ProTcl is a Prolog interface to Tcl/Tk. It has a very simple
   interface, which just allows one to evaluate Tcl expressions from
   Prolog. It has been tested on ECLiPSe and SICStus, on a Sparc 10.
   ProTcl is available by anonymous ftp from
      ftp.ecrc.de:/pub/eclipse/progs/protcl/
   Send comments and suggestions to Micha Meier <[e-mail]>.

----------------------------------------------------------------
Subject: [1-7]  Mailing Lists

Prolog and Logic Programming:
   [e-mail] (general)
   [e-mail] (nitty gritty)

   All requests to be added to or deleted from this list, problems,
   questions, etc., should be sent to [e-mail]

   [The host sushi.stanford.edu no longer exists, as of 11/24/92.
    Does anybody know the new location of the mailing lists?]

Lambda Prolog:
   [e-mail]

   To subscribe, send mail to [e-mail].

Electronic Journal of Functional and Logic Programming (EJFLP)

   EJFLP is a refereed journal that will be distributed for free via e-mail.
   The aim of EJFLP is to create a new medium for research investigating the
   integration of the functional, logic and constraint programming paradigms.

   For instructions on submitting a paper, send an empty mail message with
      Subject: Help
   to:
      [e-mail].
   You will receive an acknowledgment of your submission within a few hours.

   To subscribe to the journal, send an empty mail message to the following
   address:
       [e-mail]
   You will receive an acknowledgment of your subscription within a few days.

   If there are any problems with the mail-server, send mail to
   [e-mail].

   The editorial board is: Rita Loogen (RWTH Aachen), Herbert Kuchen (RWTH
   Aachen), Michael Hanus (MPI-Saarbruecken), Manuel MT Chakravarty (TU
   Berlin), Martin Koehler (Imperial College London), Yike Guo (Imperial
   College London), Mario Rodriguez-Artalejo (Univ. Madrid), Andy Krall
   (TU Wien), Andy Mueck (LMU Muenchen), Tetsuo Ida (Univ. Tsukuba,
   Japan), Hendrik C.R. Lock (IBM Heidelberg), Andreas Hallmann (Univ.
   Dortmund), Peter Padawitz (Univ. Dortmund), Christoph Brzoska (Univ.
   Karlsruhe).

PDC-L:
   [e-mail] is a discussion list for PDC Prolog users.

   To subscribe, send mail to [e-mail] with
       SUBSCRIBE PDC-L <your full name>
   in the message body.

Theorem Provers:
   [e-mail]

   This (unmoderated) list is intended for announcements of interest to
   people interested in automated theorem proving.

   To subscribe, send your email address to [e-mail].

Type Theory:
   [e-mail]

   Moderated mailing list about type theory. Archived on
      theory.lcs.mit.edu:/pub/meyer/

   To subscribe, send mail to [e-mail].

Logic:
   [e-mail]

   Moderated mailing list about logic. Archived on
      theory.lcs.mit.edu:/pub/meyer/

   To subscribe, send mail to [e-mail]

----------------------------------------------------------------
Subject: [1-8] Books and Magazine Articles

A BiBTeX bibliography of Logic Programming Conferences is available by
anonymous ftp from duck.dfki.uni-sb.de. See [1-2] above.

A partially annotated bibliography of work on integrating
object-oriented and logic programming is available by anonymous ftp
from menaik.cs.ualberta.ca:/pub/oolog/ in PostScript and BibTeX
formats. Written by Vladimir Alexiev <[e-mail]>.

The following books are regarded as popular and widely used. Also
included are some books about WAM. This is not intended to be a complete
Prolog bibliography.

Prolog Programming:

   Covington, Michael A.; Nute, D.; and Vellino, A. "Prolog
   Programming in Depth", Scott, Foresman & Co., 1987. ISBN 0-521-40984-5
   (Out of print, but new edition coming soon. Copies of the 1987
   edition are still available from the University of Georgia
   Bookstore, at 706-542-7131.)

   Clocksin, W.F. and Mellish, C.S: "Programming in Prolog", 3rd Ed.
   Springer Verlag, 1987, $29. ISBN 0-387-17539-3, 281 pages. (Basic
   Introduction).

   Conlon, Tom: "Programming in Parlog". Addison-Wesley, 1989,
   ISBN 0-201-17450-2.

   Dawe, C.M. and M.S. Dawe, "Prolog for Computer Science", Springer
   Verlag, 1994. ISBN 0-387-19811-3, 190 pages, $35. (Intro to
   computer science using Prolog.)

   Dodd, Anthony, "Prolog: A logical approach", Oxford University
   Press, New York, 1990, 556 pages. ISBN 0-198-53822-7 (cloth), $52.50;
   ISBN 0-198-53821-9 (paperback), $26.00.

   Kluzniak and Szpakowicz: "Prolog for Programmers", Academic Press 1985

   G. L. Lazarev, "Why Prolog? Justifying Logic Programming for Practical
   Applications", Prentice Hall, 1989. [Software engineering bent.
   Emphasizes advantages of declarative programming.]

   Le, Tu Van,  "Techniques of Prolog programming, with implementation
   of logical negation and quantified goals", John Wiley, New York, 1993.
   ISBN: 0-471-57175-X (American edition), 0-471-59970-O (International
   edition).  LnProlog, a Prolog interpreter that supports negative
   finding queries and quantified queries is available together with
   the book.

   Leon Sterling, editor, "The Practice of Prolog", MIT Press, 1990.
   342 pages, ISBN 0-262-19301-9, $39.95.

Advanced Prolog Programming:

   O'Keefe, Richard A., "The Craft of PROLOG", MIT Press, 1990, 410 pages.
   ISBN 0-262-15039-5, $42.50.

   Peter Ross, "Advanced Prolog: Techniques and Examples",
   Addison-Wesley, 1989, ISBN 0-201-17527-4.

   Leon Sterling and Ehud Shapiro, "The Art of Prolog: Advanced
   Programming Techniques", 2nd Edition, MIT Press, 1994. 688 pages,
   ISBN 0-262-19338-8, $49.95.
   [Source code for the book is available in ftp.cwru.edu:/ArtOfProlog/.
    There is a subdirectory for each chapter of the book containing the
    text of the programs in that chapter.]

AI and Prolog:

   Yoav Shoham, "Artificial Intelligence Techniques in Prolog", Morgan
   Kaufmann Publishers, 1993, 400 pages. ISBN 1-55860-167-8 (paper) $39.95.
   ISBN 1-55860-319-0 (cloth) $49.95. [Topics include search, backward
   chaining, data-driven methods, truth maintenance, constraint
   satisfaction, reasoning with uncertainty, planning, temporal
   reasoning, machine learning, and natural language processing. Prolog
   source for all the programs in the book is available by anonymous ftp
   from unix.sri.com:/pub/shoham/]

   Bratko, Ivan, "Programming in Prolog for Artificial Intelligence",
   2nd Edition, Addison-Wesley, 1990. [Good introduction to Prolog and AI.
   A bit large, though, for an Intro to Prolog course. Includes
   discussion of the 8-queens problem.]

   Dennis Merritt: "Building Expert Systems in Prolog", Springer-Verlag 1989.
   Explains how to build various expert system shells in Prolog, including
   forward/backward chaining, FOOPS, rete-network, frames, solving
   Rubik's cube and more. Includes complete source code listings.
   (Source code from the book is also sold on disk by Amzi!.)

   Dennis Merritt: "Adventure in Prolog", Springer-Verlag, 1990.
   ISBN 0-387-97315-X, ISBN 3-540-97315-X.  $34
   Teaches Prolog by leading the reader through the construction of an
   adventure game. The exercises lead the reader through three other
   programs:  an intelligent database, an expert system and an order-entry
   program.  While most texts teach Prolog with fragments of interesting code,
   this book takes a more pragmatic (as opposed to theoretical approach) and
   shows the reader how to assemble complete Prolog programs.

   Gazdar, G. and Mellish, C., "Natural Language Processing in Prolog:
   An Introduction to Computational Linguistics", Addison-Wesley,
   Reading, Massachusetts, 1989. (There are three different editions
   of the book, one for Lisp, one for Prolog, and one for Pop-11.)

   Fernando C.N. Pereira and Stuart M. Shieber, "Prolog and
   Natural-Language Analysis", CSLI Lecture Notes Number 10, Stanford,
   CA, 1987. 286 pages, ISBN 0-937073-18-0.

   Michael A. Covington, "Natural Language Processing for Prolog
   Programmers", Prentice-Hall, Englewood Cliffs, NJ, 1994. ISBN
   0-13-629213-5.

   Harvey Abramson and Veronica Dahl, "Logic Grammars", Springer-Verlag,
   New York, 1989, 234 pages, ISBN 0-387-96961-6.

   Peter Flach, "Simply Logical: Intelligent Reasoning by Example",
   John Wiley & Sons, 1994, 256 pages. ISBN 0-471-94152-2 paper ($31.95).
   [Covers theoretical and practical aspects of Prolog programming as well
   as AI topics like knowledge representation, search, heuristics,
   abduction, default reasoning, and induction. Every technique is
   accompanied by a Prolog program that implements it. More information
   about the book is available from
      http://machtig.kub.nl:2080/Infolab/Peter/SimplyLogical.html
   or by email from [e-mail].]

Logic Programming:

   Hogger, C.J.: "Introduction to Logic Programming", Academic Press 1984

   Kowalski, R.A.: "Logic for Problem Solving", New York 1979, Elsevier Publ.

   LLoyd, John: "Foundations of Logic Programming", 2nd Edition,
   Springer-Verlag, 1988. (Intro to logic programming theory.)

   David Maier and David S. Warren: "Computing with Logic: Logic
   Programming with Prolog", Benjamin Cummings, Menlo Park, CA, 1989.

   Nilsson, Ulf and Maluszynski, Jan, "Logic, Programming and Prolog",
   John Wiley & Sons, 1990, ISBN 0-471-92625-6.

   Subrata Kumar DAS, "Deductive Databases and Logic Programming",
   Addison-Wesley Publishing Company, July 1992, 448 pages.
   ISBN 0-201-56897-7.

Constraint Logic Programming and Constraint Satisfaction:

   Bennaceur, Hachemi and Gerard Plateau, "An exact algorithm for the
   constraint satisfaction problem: Application to logical inference",
   Information Processing Letters 48(3):151-158, November 19, 1993.

   Cohen, J., "Constraint Logic Programming Languages", Communciations
   of the ACM 33(7):52-68, 1992. [Good introduction to CLP and
   includes a historical overview.]

   Freeman-Benson, B.N., Maloney, J., and Borning, A., "An Incremental
   Constraint Solver", Communications of the ACM 33(1):54-63, 1990.
   [Includes a good reading list on the history and applications of
   constraints.]

   Freuder, Eugene C., and Richard J. Wallace, "Partial constraint
   satisfaction", Artificial Intelligence 58(1-3):21-70, December 1992.

   Van Hentenryck, Pascal, "Constraint Satisfaction in Logic Programming",
   MIT Press, Cambridge, MA, 1989, ISBN 0-262-08181-4.

   Jaffar, Joxan and Jean-Louis Lassez, "Constraint Logic Programming", in
   Proceedings of the 14th ACM Symposium on Principles of Programming
   Languages (POPL), Munich, Germany, pages 111-119, 1987.
   [A longer version appears in Joxan Jaffar and Jean-Louis Lassez,
   "Constraint Logic Programming", Technical Report 86-74, Monash
   University, Victoria, Australia, June 1986.]

   Kumar, Vipin, "Algorithms for Constraint-Satisfaction Problems: A
   Survey", AI Magazine 13(1):32-44, 1992.

   Mackworth, Alan K., "The logic of constraint satisfaction", Artificial
   Intelligence 58:3-20, 1992.

   Meseguer, P., "Constraint Satisfaction Problems: An Overview", AICOM
   2(1):3-17, 1989.

   Steele, Guy L., "The Definition and Implementation of A Computer
   Programming Language Based on Constraints", PhD thesis, MIT, 1980.

   Tsang, E., "Foundations of constraint satisfaction", Academic Press, 1993.
   ISBN 0-12-701610-4.

   Zhang, Ying and Alan K. Mackworth, "Constraint Programming in
   Constraint Nets", in Position Papers for the First Workshop on
   Principles and Practice of Constraint Programming, pages 303-312,
   Newport, RI, April 28-30, 1993.

   [See also the articles on Constraint Networks (pages 276-285) and
   Constraint Satisfaction (pages 285-293) in Shapiro's Encyclopedia
   of Artificial Intelligence.]

Prolog Implementations and WAMs:

   Ait-Kaci, Hassan, "Warren's Abstract Machine: A Tutorial Reconstruction",
   MIT Press, Cambridge, MA. 1991.
   ISBN: 0-262-51058-8 paper ($17.50), 0-262-01123-9 cloth.

   Patrice Boizumault, "The Implementation of Prolog", Princeton
   University Press, Princeton, NJ, 1993.  Translated by Ara M.
   Djamboulian and Jamal Fattouh. ISBN 0-691-08757-1, 357 pages ($49.50).

   Campbell, J.A. (ed):  "Implementations of Prolog", John Wiley, 1984

   Peter M. Kogge, "The Architecture of Symbolic Computers",
   McGraw-Hill, 1991. ISBN 0-07-035596-7.
      Includes sections on memory management, the SECD and
      Warren Abstract Machines, and overviews of the various
      Lisp Machine architectures.

   David H. D. Warren: "An Abstract Prolog Instruction Set", Technical Note
   No 309, SRI International, Menlo Park, CA, 1983.

   David H. D. Warren, "Logic Programming and Compiler Writing," in
   Software-Practice and Experience 10(2):97-125, 1980.

   J. Cohen and T. Hickey, "Parsing and Compiling using Prolog",
   ACM Transactions on Programming Languages and Systems (TOPLAS),
   9(2):125-163, 1987.

   J. Paakki, "Prolog in practical compiler writing", The Computer
   Journal 34(1):64-72, 1991. (But see Letters to the Editor, The
   Computer Journal 35(3):313, 1992.)

   Jonathan P. Bowen, "From Programs to Object Code using Logic and Logic
   Programming", in R. Giegerich and S. L. Graham, editors, Code
   Generation -- Concepts, Tools, Techniques, pages 173-192,
   Springer-Verlag, 1992.

   Jonathan P. Bowen, "From Programs to Object Code and back again using
   Logic Programming: Compilation and Decompilation", Journal of
   Software Maintenance: Research and Practice 5(4):205-234, December 1993.

Parallel Prologs:

   Gregory, Steve: "Parallel Logic Programming in Parlog: The Language
   and Its Implementation", Addison-Wesley, 1987, ISBN 0-201-19241-1.

   Tick, E.: "Parallel Logic Programming". MIT Press, 1991

Miscellaneous:

   Deville, Yves: "Logic Programming, Systematic Program Development",
   International Series in Logic Programming, Addison-Wesley, 1990, 338 pages.
   ISBN 0-201-17576-2.

   Wolfram, D.A., "The Clausal Theory of Types", Cambridge Tracts in
   Theoretical Computer Science {\bf 21}, Cambridge University Press,
   1993.

Magazine Articles:

   PCAI Magzine, September/October 1993. Article on exploring Prolog,
   showing the first steps to four applications -- an adventure game, an
   object-oriented shell, a tax program, and an animal guessing game.
   An excerpt of this article is available from
      ftp.cs.cmu.edu:/user/ai/lang/prolog/doc/intro/explore.doc

   BYTE Magazine, August 1987. 5 introductory articles on Prolog.
   Applications include logic grammars and simulating a microprocessor.

   Uwe Schreiweis: Beredte Logik, Konzepte der 'KI-Sprache" Prolog,
   (Eloquent Logic, Concepts of the AI language Prolog), iX Magazine,
   October 1992, pages 84-90.

   Uwe Schreiweis: Basis der Fuenf, Die Sprache Prolog in der Public
   Domain, (Base of the Five, Prolog in the Public Domain), iX Magazine,
   October 1992, pages 92-94.

   Uwe Schreiweis: Fuenfte Generation, Kommerzielle Prolog-Systeme,
   (Fifth Generation, Commercial Prolog Systems), iX Magazine, October
   1992, pages 96-102.

   Klaus Bothe: Weniger Raum, Speicherplatzbezogener Prolog-Benchmark,
   (Less Space, A Space Oriented Prolog Benchmark), iX Magazine, October
   1992, pages 106-7.

Magazines Related to Prolog:

   Logic Programming Newsletter (4 issues/yr)
   Included with membership in the Association for Logic Programming
   ($20 regular, $10 students). For membership information, write to
   Cheryl Anderson (ALP), DoC-ICSTM, 180 Queens Gate, London SW7 2BZ,
   UK, phone [phone] x5011, fax [phone], or send email
   to [e-mail]. Contributions are welcome and should be sent
   to Andrew Davidson <[e-mail]>.

   AI Communications (4 issues/yr)
   "The European Journal on Artificial Intelligence"  ISSN 0921-7126,
   European Coordinating Committee for Artificial Intelligence.

   AI Expert (issued monthly) ISSN 0888-3785, Miller Freeman Publishers
   See a copy of the magazine for list of BBS's in NA. On CompuServe: GO
   AIEXPERT. Regularly reviews Prolog interpreters and compilers.

   Expert Systems (issued Feb, May, Aug and Nov) ISSN 0266-4720,
   Learned Information (Europe) Ltd. Subscription: GBP 85 or USD 110

   IEEE Expert (issued bimonthly) ISSN 0885-9000, IEEE Computer Society

   The Journal of Logic Programming (issued bimonthly), (North-Holland),
   Elsevier Publishing Company, ISSN 0743-1066

   New Generation Computing, Springer-Verlag. (LOTS of Prolog in it.)

----------------------------------------------------------------
Subject: [1-9] Is there a straight-forward way of compiling Prolog to C?

Two methods of compiling Prolog to C have been reported in the
literature:
   -  WAM-based approaches
   -  Continuation-based approaches

The WAM-based approach compiles Prolog programs into a sequence of C
function or macro calls to WAM instructions. A brief description of
this method and some results are given in the paper:

   Michael R. Levy and R. Nigel Horspool, "Translating Prolog to C: a
   WAM-based Approach", in Proceedings of the Second Compulog Network
   Area Meeting on Programming Languages, and the Workshop on Logic
   Languages in Pisa, May 1993. (Available by anonymous ftp from
   csr.uvic.ca:/pub/mlevy/.)

A "quick-and-dirty" method is to implement the WAM functions as described
in Ait-Kaci's tutorial, to label each call with a C case label, and then throw
a giant switch(P) statement around the entire sequence of calls, where P
is the WAM program counter.  On return from any instruction that modifies
P, a "goto Start" must be inserted. (This method was posted by Rob
Scott, <[e-mail]>, based on the JANUS papers by Saraswat.)

This strategy will work, but does not allow you to modularize your
prolog program. Predicates in prolog seem to generate 8 to 15 WAM
instructions per clause, so (assuming very roughly a clause per
line)you might expect your 1,000 line program to expand to a switch
statement containing up to 15,000 lines. Some C compilers can't handle
such a big switch statement.

Levy and Horspool solve this problem by compiling each Prolog
predicate to a seperate C function. A dispatch loop mechanism is used
to call the C functions. C switch statements are used only inside the
functions.  A predicate that calls another predicate sets P to contain
the address of the C function that implements the called predicate,
(and sets another register called W in their scheme) and then returns
to the dispatcher instead of calling the predicate. This bypasses the
C run-time stack.  This lets one exploit WAM optimizations (like LCO)
and yet retain the ability to create many modules. Their system
performs well when compared with byte-code compilers, but translated
code runs slower than code produced by native code compilers.  On the
other hand, it outputs portable ANSI C that can run on any machine
with a C compiler.

Other approaches to translating to C use continuations. The idea here
is to translate every Prolog predicate to a C function that has
an additional argument, namely a continuation function. If the function
fails, it simply returns, but if it succeeds, it executes the continuation.
When the function regains control from the continuation, it can then try
to generate a new solution. Here are two references
that describe systems built using continuations:

   J. L. Weiner and S. Ramakrishnan, "A Piggy-Back Compiler for Prolog",
   in Proceedings of SIGPLAN T88 Conference on Programming Language
   Design and Implementation, Atlanta, Georgia, 1988, pages 288-296.

   J. L. Boyd and G. M. Karam, "Prolog in C", Carleton University,
   Ottawa, 1988.

Oliver Ridoux <[e-mail]> reports that a
continuation-based approach works well when used to compile
LambdaProlog. His scheme translates every predicate into a function
that uses and modifies the success and failure continuations, with
recursion in the predicate becoming iteration in the continuation
passing mechanism. Inside the function one uses whichever intermediate
machine one fancies. Clauses within the function can be either the
branches of a switch statement or simply labelled when using a C
system that can store labels. This approach can still generate
monstrous C programs that blow up the C compiler, but the C programs
aren't as large as those generated by a one module to a function
scheme. Approaches that replace recursion in a predicate with
recursion in a function tend to overload the C stack and lead to
sloppy memory management.  Two technical reports describing Ridoux's
approach are available by anonymous ftp from
   ftp.irisa.fr:/
as pm/*.ps.Z and mailv06/*.ps.Z.

Michael Covington <[e-mail]> points out that a very simple
approach is to write a Prolog interpreter in C, then store the Prolog
program in that program's data! This will, of course, execute slowly.
One might imagine all sorts of other schemes. For example, a query
could be treated as a stack of "suspensions" (with the left-most goal
on top).  The top suspension is executed by selecting the appropriate
clause (possibly using indexing), and then, if necessary, pushing new
suspensions on the stack (the body of the clause whose head unified
with the current suspension).

Another question to ask is this: Is there any reason why you should want to
convert Prolog to C at all? George Saab of Quintus Corp. pointed out that,
with Quintus Prolog, you can create a standard .o file from a Prolog file,
which can then be linked with your other .o files to create an executable.
What's more, your Prolog code can be called from C code and vice versa.

On ther hand, the advantage of distributing "Prolog objects" as C rather than
.o files is portability.

M. Gaspari  and G. Attardi describe an approach to translating Prolog to C
based on the provision of a common runtime architecture. This is
described in

   G. Attardi and M. Gaspari, "Multilanguage Interoperability", in
   Proceedings of The 3rd International Symposium, PLILP 91,
   Springer Verlag, LNCS #528, 1991.

[Note: Thanks to Michael Levy, Department of Computer Science,
University of Victoria, <[e-mail]>, for writing this section.]

----------------------------------------------------------------
Subject: [1-10] WAM emulators and tracers

Johan Bevemyr's Luther-based WAM-tracer is available by anonymous ftp
from Uppsala University in Sweden. It includes a simple compiler from
Prolog to WAM code and a low-level WAM code tracer written in
emacs-lisp.  The tracer splits the screen into regions to show
data-areas, registers, and so on. You can then step through running
the code. The tracer is available by anonymous ftp from
   ftp.csd.uu.se:/pub/WAM-tracer/luther.tar.Z
Documentation on the tracer is included in the distribution.  The
emulator is in the /pub/WAM-emulator/ directory (and runs in SICStus
Prolog).  For more information, contact Johan Bevemyr
<[e-mail]> or <[e-mail]>.

----------------------------------------------------------------
Subject: [1-11] What is the Basic Andorra Model and AKL?

The Basic Andorra Model is a way to execute definite clause programs
that allows dependent and-parallelism to be exploited transparently.
It also supports nice programming techniques for search programs.  The
idea is to first reduce all goals that match at most one clause.  When
no such goal exists, any goal (e.g., the left-most) may be chosen.
The BAM was proposed by David H. D. Warren, and his group at Bristol
has developed an AND-OR parallel implementation called Andorra-I,
which also supports full Prolog.  See, for example,

   Seif Haridi and Per Brand, "Andorra Prolog, an integration of Prolog
   and committed choice languages", in Proceedings of the FGCS 1988,
   ICOT, Tokyo, 1988.

   Vitor Santos Costa, David H. D. Warren, and Rong Yang, "Two papers on
   the Andorra-I engine and preprocessor", in Proceedings of the 8th
   ICLP. MIT Press, 1991.

   Steve Gregory and Rong Yang, "Parallel Constraint Solving in
   Andorra-I", in Proceedings of FGCS'92. ICOT, Tokyo, 1992.

AKL (Andorra Kernel Language) is a concurrent constraint programming
language that supports both Prolog-style programming and committed
choice programming.  Its control of don't-know nondeterminism is based
on the Andorra model, which has been generalised to also deal with
nondeterminism encapsulated in guards and aggregates (such as bagof)
in a concurrent setting. See, for example,

   Sverker Janson and Seif Haridi, "Programming Paradigms of the Andorra
   Kernel Language", in Proceedings of ILPS'91. MIT Press, 1991.

   Torkel Franzen, "Logical Aspects of the Andorra Kernel Language", SICS
   Research Report R91:12, Swedish Institute of Computer Science, 1991.

   Torkel Franzen, Seif Haridi, and Sverker Janson, "An Overview of the
   Andorra Kernel Language", In LNAI (LNCS) 596, Springer-Verlag, 1992.

   Sverker Janson, Johan Montelius, and Seif Haridi, "Ports for Objects
   in Concurrent Logic Programs", in Research Directions in Concurrent
   Object-Oriented Programming, MIT Press, 1993 (forthcoming).

The above papers on AKL are available by anonymous ftp from
   sics.se:/pub/ccp/papers/
An (as yet non-released) prototype implementation of AKL is available
for research purposes (contact [e-mail]).

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Subject: [1-12] What is Constraint Logic Programming?

Constraint Logic Programming (CLP) augments Prolog by adding
constraints to the clauses. The CLP implementation solves goals in the
same manner as Prolog, but also merges the constraints associated with
each rule. If the merge succeeds, the successful goal and the
corresponding constraints are returned. If, however, the constraints
are mutually exclusive, the solution fails.

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Subject: [1-13] How do you write portable programs in Prolog?

The de-facto standard syntax for Prolog is known as the Edinburgh
standard. It is based on the syntax of DEC-10 Prolog, an early Prolog
implementation developed at the University of Edinburgh.
See question [1-1] for information on the draft ISO standard for
Prolog.

Unfortunately, not every Prolog implementation is Edinburgh compatible.
There also isn't any notion of read-conditionalization, like #+ and #-
*features* in Common Lisp.

One option is to use the C preprocessor on Prolog code before loading
it into Prolog.  Or you could use term-expansion to roll your own
conditional compilation system. Term expanding a clause to []
effectively discards it.

Another possibility is to conditionalize the execution instead of the
compilation. The user would have to uncomment a line like one of the
following,
   % this_is(quintus).
   % this_is(sicstus).
and the code would have to test for the proper literal
   a :- this_is(quintus), blah, blah, blah.
   a :- this_is(sicstus), blah, blah, blah.
at a slight cost in efficiency. (If you first feed the program through
a general partial evaluator, you'll get an equivalent program without
the inefficiency. Partial evaluation is in some sense a more powerful
and semantically cleaner form of source preprocessing. Given
        <head> :- <condition>, <rest of body>.
If <condition> is always false, we can safely drop the clause. If
<condition> is always true, we can drop it from any clauses that
include it.)

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