🚀 go-pugleaf

In article <273@gould.doc.ic.ac.uk> cdsm@doc.ic.ac.uk (Chris Moss) writes:
>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.

I think it is very important to distinguish this -- that Richard
thinks (if indeed he does) that the details of Edinburgh Prolog
represent a good way of doing Prolog -- from the main point of
Richard's argument in this discussion, namely that the standard
should be based on the langauge as it is and without so many changes
that it becomes in effect a new language and so causes more problems
for current users than it solves.

It would be fair to answer Richard by showing that the changes are
not so great as to make it a different language, by showing that
the benefits are enough to justify the cost of change, or by admitting
(if it's so) that the standards committees intend to make a new and
better Prolog as they go -- that they are working under a different
notion of standardization -- or even that the goal is not a standard
for Edinburgh Prolog but for a wider class of dialects.

It is, I think, at least misdirection to answer Richard by saying
that the people on the committee beleive in the solutions they
promote, that Richard believes in the solutions he promotes, that
of course no one is unbiased, that Richard can't escape his position
as a Quintus employee and that people might take note of this, and so
on: that, in effect, everyone has their prejudices and Richard's
just happen to be towards Edinburgh Prolog.

These things may all be true, but by "misdirection", I mean a
reminder that Richard has raised some issues that deserve a direct
answer.  Just because Richard might be inclined towards Edinburgh
Prolog in any case doesn't mean he isn't right when he says the BSI
proposals go too far beyond codifying current practice or that users
will find the cost of conversion too high.

>You have made your case and I intend to make sure the committee
>understand it.

Richard may well be underestimating the extent to which you're 
doing this.  That you're carrying on this discussion counts for
something too.

Nonetheless, there are times when you seem to be muddying the waters
rather than responding fairly to what Richard said.  I am not saying
that is your intention, but it is sometimes what happens.

For example, here is the exchange that began the issue of
"personalities":

In article <845@cresswell.quintus.UUCP> ok@quintus.UUCP (Richard A.
O'Keefe) wrote:
- It is very easy to deny that the early work was based on Edinburgh
- Prolog: some of the early stuff looked uncommonly like Sigma Prolog.
- Indeed, document PS/69 (dated 6 June 1985) explicitly says that the
- standard was now to be based on micro-PROLOG as well as C&M.

In <256@gould.doc.ic.ac.uk>, you quoted Richard's remark and replied:
+ I work in the same establishment as the authors of SigmaProlog.
+ I'm not going to start badmouthing them on the net.

I don't see anything in the passage you quoted that amounts to
badmouthing the authors of Sigma Prolog -- or did you mean that
*you* weren't going to badmouth them because you worked in the
same place?  

Richard was responding to an earlier claim that it was hard to deny
the work was based on Edinburgh Prolog.  Specifically, in
<249@gould.doc.ic.ac.uk>, you said:

   I doubt anyone could deny that our work is based on Edinburgh
   Prolog as described in Clocksin & Mellish. But should it be
   limited precisely to that?

The actual disagreement seems to be that Richard had in mind "based on
E.P. alone" while you had in mind "based on E.P. and other Prologs".
Richard brought in PS/69 to give some concrete backing to his "looked
uncommonly like", so that it would be clear that his remark was not
based on a mere impression.  As you know, this is the way Richard
writes.  If you suggest that no one can deny something and he does
deny it he will tell you so and give reasons besides.  But I do
not think he had personalities in mind.

Another example is the following:

In article <845@cresswell.quintus.UUCP> ok@quintus.UUCP (Richard A. O'Keefe) writes:
- The phrase "as described in" is perhaps ambiguous.
- Reading 1:
-	"Edinburgh Prolog (that is, exactly what is in Clocksin & Mellish)".
- Reading 2:
-	"Edinburgh Prolog (that is, the dialects that Clocksin & Mellish
-	refer to and partly describe)".
- Since C&M is far too vague about details to serve as the basis for a
- standard, I find reading 2 the most plausible one.

In <256@gould.doc.ic.ac.uk>, you replied:
+ I don't find Reading 2 any more plausible than my original.

+ "Clocksin and Mellish were trying to describe what was going on at
+ Edinburgh. Therefore one takes not what they said but what they were
+ trying to say, which is obviously...  (insert one's own prejudice)"

There is certainly an argument to be made here, namely that the
pahrase cannot be clarified as easily as Richard suggests.  But
your rephrasing of Reading 2 is hardly a fair one.  It is not just
a question of one prejudice verses another: there are facts involved,
and Richard is an expert on those facts.  Nor is it right to say
Clocksin and Mellish were "trying to describe what was going on
at Edinburgh".  They described a "core Prolog".

Then there is the question of how different the Edinburgh Prologs are
from each other compared to their distance from the BSI proposals.
This, at least, seems largely a technical issue: we can look at the
differences and see which are greater.  So far, though, only Richard
has tried to explain his accounting by citing examples.

Each side has accused the other of making misleading statements.

>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 will leave the question as to whether that is or is not misleading
to further discussion.  But in <256@gould.doc.ic.ac.uk> you said:

+ Unfortunately, since the breakup of the original Edinburgh group centred 
+ round the DEC10 implementation there has really been no coherence at all.
+ Poplog, NIP, Prolog-X all come from the right stable but vary in many
+ details. To those further afield it is even more confusing.

That is certainly (at least) misleading, as Richard has pointed out.
"No coherence at all" is certainly too strong as well as going further
than Richard's "far more different".

One of the goals of the NIP effort was to retain substantial
compatibility with DEC-10 Prolog, and it has done so.

I have recently taken a moderately large program written for Quintus
Prolog and run it successfully, without change, in the present NIP.
Richard is well qualified to judge whether this represents a general
possibility or is a fortuitous accident, because he does know a great
deal about the different Prologs both in and outside the Edinburgh
group.

If, however, he is wrong, and the Edinburgh Prologs are not
"***MUCH*** closer to each other than any of them is to the current
BSI fragments", the Prolog community should be told why, in detail,
for otherwise they will rightly conclude that Richard's case is the
stronger.

Finally, there is the question of the correspondence between Richard's
position and the interest of Quintus.

>>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.

The point is that Richard *wasn't* arguing for a standard to be
based on *Quintus* Prolog.  Edinburgh Prolog is not the same thing
as Quintus Prolog.  That Richard is arguing for a standard based on
Quintus is simply false regardless of his motives.

One might note, from my address below, that I am at Edinburgh.
I should therefore add that any speculation on the influence of that
fact on my position in this discussion is just that: speculation.
For all anyone knows, I would prefer a standard based on Prolog II.

Jeff Dalton,                      JANET: J.Dalton@uk.ac.ed             
AI Applications Institute,        ARPA:  J.Dalton%uk.ac.ed@nss.cs.ucl.ac.uk
Edinburgh University.             UUCP:  ...!ukc!ed.ac.uk!J.Dalton