bts (11/29/82)
Greetings! This group has been created as a forum for discussions of the Prolog programming language and logic programming in general. One of the first things I'd like to see is information on which Prolog implementations people are using, what they think of them, where they got them, etc. This seems to be the most common Prolog request on the net, so let's share what we know. At UNC, we have the Edinburgh UNIX Prolog, written in PDP-11 assembly language. It's running on one of our VAX 11/780s (4.1bsd), using the 'compat' compatibility mode package. We found compat lurking in /usr/src/games, where it was being used by Zork and a few of the older games. There is almost no documentation on compat. Thanks to hints from John Lloyd at the University of Melbourne, we were able to fix compat to work with Prolog. (If anyone is interested, I can mail the details.) This UNIX Prolog is very similar to the Prolog described in Clocksin and Mellish's book "Programming in Prolog". That's not surprising, since they were the authors of this interpreter, too. There are three problems: (1) It is restricted by the PDP-11 address space, so compu- tations frequently run out of memory. (It gives you a nice "infinite loop" error message when this happens.) (2) Every now and again, compat becomes confused by inter- rupts and bombs. (3) There is no compiler. If you're interested in UNIX Prolog, the person to write to is Robert Rae, Chief Systems Programmer Department of Artificial Intelligence University of Edinburgh Edinburgh, EH1 2QL Scotland U.K. We'd like to have a Prolog which would give us a com- piler and which would take advantage of the VAX's address space. It would have to run under UNIX. One written in C might be best, particularly if we were free to modify it. I'm hoping that one of you will suggest a Prolog for us. One final comment about the group. If you know Prolog users who're not on USENET, please forward this to them. I'm willing to do a small amount of re-mailing of articles to people on ARPA or CSNET and to submit articles from them to the group. Thanks, again, for the yes votes. Bruce Smith, UNC-Chapel Hill duke!unc!bts bts.unc@udel-relay