Path: utzoo!mnetor!uunet!seismo!sundc!pitstop!sun!quintus!ok From: ok@quintus.UUCP (Richard A. O'Keefe) Newsgroups: comp.lang.prolog Subject: Re: BSI Prolog terms of reference Message-ID: <917@cresswell.quintus.UUCP> Date: 30 Apr 88 01:17:21 GMT References: <831@cresswell.quintus.UUCP> <249@gould.doc.ic.ac.uk> <273@gould.doc.ic.ac.uk> Organization: Quintus Computer Systems, Mountain View, CA Lines: 141 Keywords: promises In article <273@gould.doc.ic.ac.uk>, cdsm@ivax.doc.ic.ac.uk (Chris Moss) writes: [about Frank McCabe & Sigma Prolog] "Edinburgh" Prolog and SigmaProlog are obviously related languages, just like FORTRAN and BASIC. It is not that I claim that Frank McCabe's ideas are in any way inferior to the ideas in Edinburgh Prolog. Only that they are incompatible. Trying to smuggle Sigma Prolog ideas (such as its data structures) into a standard which was supposed to be a standard for "Edinburgh Prolog as described in Clocksin & Mellish" made about as much sense as adding BASIC's READ and DATA statements in a standard for FORTRAN. > I'm not trying to "bring personalities into it" but in the real world > it is often the easiest way to explain positions. You, Richard, > believe in the nuances of "Edinburgh Prolog" partly because you use > it every day, have contributed many valuable details to it, and see > your ideas worked out in it. Use it every day, yes. Have contributed valuable details to it, not that I know of. (Off-hand, I can think of only two details of DEC-10 Prolog that I can claim responsibility for, and "Edinburgh" Prolog imitations have widely ignored them.) See my ideas worked out in it? _Which_? It is not a question of "believing in nuances of" anything. If the BSI committee went off and decided to produce a standard identical to Z-Prolog, I'd keep quiet about it. My position is simply that if a group claim to be developing a standard for "Edinburgh Prolog" (rather than LM Prolog, microPROLOG, IC Prolog, LogLisp, PROLOG/KR, or any of several dozen related languages all with _some_ merit), then that is what they should DO. If the BSI committee had done what they said they were going to do, we could have had a first draft of a usable standard ready for comment by July of 1985. Instead, the committee has indulged itself in designing a new language (I understand how great a pleasure that is; J.R.R.Tolkien called it "A Secret Vice") and by its default has materially contributed to the present diversity of Prologs. > I deliberately phrase that in almost religious terms, because it's > often not a question of that's right and the other's wrong, but > rather six of one and half a dozen of the other. Again, I'm not arguing that "Edinburgh" Prolog is right and SuperLogLisp is wrong. The point is consistency, comprehensibility, coherence. > You have made your case and I intend to make sure the committee > understand it. I don't agree that it is "far more different from any > two of those existing systems than they are from each other." That's > a misleading statement that could prejudice people who haven't taken > the trouble you have to analyse the documents. (I'll follow up on the > "var" question tomorrow. It's a DETAIL though obviously an important > one.) How can the truth be misleading? With all the earnestness I possess, I assure all who read this that it is my sincere belief based on careful reading of the BSI fragments and of various Prolog manuals that it would be easier for me to convert a program from AAIS Prolog to Arity Prolog than to convert from either to BSI Prolog, and that this applies to every other pair of "Edinburgh-compatible" Prologs I am familiar with. I believe that anyone who is not biassed by being a member of the BSI/AFNOR group or does not work for one of two Prolog vendors I have in mind but won't name for fear of legal consequences will come to the same conclusion that I have come to after reading the documents. I am willing to lend my copies of the BSI fragments to anyone in the Bay Area. I am shocked that Chris Moss can dismiss something that will break thousands of programs as a DETAIL. (We can all agree that type testing predicates which fail quietly when given a variable are not good logic. But the BSI committee are supposed to be designing a standard for the language we already have, and I don't know of any "Edinburgh Prolog" dialect where integer(_) is an error.) > >I am deeply offended that Chris Moss should suggest that I am arguing > >for my employers rather than for what is technically good. > Richard, this time I have to take YOU to task for not reading what I > wrote, but for the implication of what you thought I might have > written. I wrote: > I don't object to you arguing for the standard to be based on Quintus. > You might be considered to be failing your employers if you didn't. Yes, I know that's what you wrote, and it's not only what I thought you might have written, it's what I thought you did write. The first sentence presupposes that I "argue for the standard to be based on Quintus". This is simply untrue. What I want in the standard now is almost exactly what I wanted in the standard in 1984 (though I've learned a little bit more about floating-point since). There are things in Quintus Prolog (such as I/O predicates with stream parameters) that I most emphatically do _not_ want in the standard, and would rather weren't in Quintus Prolog. There are plenty of details in the present Quintus Prolog system which could stand improvement (and _are_ being improved). There are several things which are _not_ in Quintus Prolog that _should_ be in the standard. I may well need Chris Moss's pardon for other offences, but NOT for "arguing for the standard to be based on Quintus [Prolog]". > It is others who might make the judgement, not me. You can't escape > from being in the position you are, and I'm sure your employers > allow you to contribute to the net because they feel they (at least) > do not lose by it. Combine this with the two previously quoted sentences, and I understand Chris Moss to be saying " Hey Richard, I know that you're not CONSCIOUSLY arguing for Quintus Prolog to be the standard just because you work there and that's what you are used to and so on. But that IS the reason. " Perhaps this is not what Chris Moss _means_, but I think it is a reasonable interpretation of what he _wrote_. One of the reasons that I am angry with the BSI committee is that I want a nice clear technically sound Prolog standard so that I can beat Quintus over the head with it and make them change a few things. Only a few, mind. > And what I would say is "we need a better forum for taking this > forward". It was a sad day for the BS committee when you flew off to > the States, Richard. Communication has been difficult across 8,000 > miles (even tho you've tried hard). Well, actually, where I flew off to was New Zealand. 13,000 miles isn't a lot easier to communicate across than 8,000, of course. The greatest barrier to communication, as far as I'm concerned, has been that whenever I've sent anything to the BSI committee, the result has been a deafening silence. (I _have_ had prompt acknowledgements from Roger Scowen and Tony Dodd when sending things to them personally, and Tony Dodd _has_ quoted some of my comments in one or two of the PS/documents. Rather, he has MISquoted me.) It was the better part of three years before I heard that the BSI committe had rejected the formal definition I sent them, for example. I cannot pretend that this has left me unbiassed. I gave up sending comments to the BSI committee when I was told that 100 pages of comments was far too much for them to distribute. One thing that bothers me about the BSI substandard is that there are a number of serious portability problems which have simply never been raised. Once you have a standard language, you still have to cope with environment differences. I can think of four things offhand which the standard utterly fails to address (only one of which is currently handled by Quintus Prolog). If the committee were so much as to issue a document explaining one of these issues and saying why they haven't resolved it, that would materially increase their credibility in my eyes. Two of them really ought to be glaringly obvious, one they can find in the Quintus Prolog manual, and the fourth should be painfully familiar to Sussex (I'm sure they have found a solution).