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Date:Mon Nov 2 15:22:30 1999 
Subject:Re: ? Unification algorithm ? 
From:Aaron Sloman See text for reply address 
Volume-ID:991102.01 

[To reply replace "Aaron.Sloman.XX" with "A.Sloman"]

Chris Glur, cglur@onwe.co.za, writes:

> Date: 29 Oct 1999 18:25:22 GMT
> Organization: The South African Internet Exchange
>
> Hi All,
>
>  Since Pop is  so  'natural' to express algorithms,
> can I find (on line) a pop implimentation of 'Unification' ?

Since Prolog is implemented in Pop-11 within poplog, there is a
unification algorithm in the file plogcore.p in the main poplog
source directory. The description of the procedure prolog_unify
is in the online REF PROLOG file, also accessible at

    http://www.cs.bham.ac.uk/research/poplog/doc/popref/prolog

If you don't have a version of poplog with sources (now freely
available, see below) have a look at:

    http://www.cs.bham.ac.uk/research/poplog/src/master/C.all/src/plogcore.p

and search for the line

    define prolog_unify(term1, term2);

There's more stuff in the same directory in the file plogterms.p

Beware: that code is written in the "system" dialect of Pop-11
and cannot simply be copied and compiled in Pop-11 by ordinary
users. However, it is mostly quite readable.
The system dialect is described in some of the files in

    http://www.cs.bham.ac.uk/research/poplog/sysdoc/

especially the syspop11 file.

> I like to read algorithms in pseudo code: with an Algol/Pascal
> type structure.     And pop is very close to this.
>
> BTW can any-person tell of sucessfully installing and running
> Poplog on Linux ?

Since poplog became freely available a lot of people have fetched and
installed the version available from here
    ftp://ftp.cs.bham.ac.uk/pub/dist/poplog/freepoplog.html
or here
    http://www.cs.bham.ac.uk/research/poplog/freepoplog.html

One of the tar files referred to in there was prepared for our students
and includes linux poplog V15.53 and tar files containing a number of
extensions to Poplog from Birmingham and Sussex, and a shell script to
do the installation.

There is a fix still to be installed to enable XVed's menus to run with
lesstif. I hope to do that soon.

>   Thanks for any replies; also to cglur@onwe.co.za  , since I often
> miss this NewsGroup.   Chris Glur.

If you wish you can join the pop-forum email list, which will forward
all comp.lang.pop postings to you automatically.

Aaron
===
-- 
Aaron Sloman, ( http://www.cs.bham.ac.uk/~axs/ )
School of Computer Science, The University of Birmingham, B15 2TT, UK
EMAIL A.Sloman AT cs.bham.ac.uk   (NB: Anti Spam address)
PAPERS: http://www.cs.bham.ac.uk/research/cogaff/