Re: Not intended for use in medical,

[dewar@merv.cs.nyu.edu (Robert Dewar)]

Robert Eachus said

<<   Jean Ichbiah was concerned about the syntax, not the addition of
the features.  Incidently, Jean was right that his syntax was
"cleaner" or looked better, but Tucker's notation was more useful
because it allowed (eventually) the separation of concepts which are
hopelessly confused in other OO languages.  The vote on the issue
reflected this, was it 2-2 with five abstentions?  (Hmmm.  I think
that the US abstained with the announced intent of changing to the
winning side, so the final was 3-2-4.)  In any case, a close decision
on a very subtle issue.

   Incidently, Tucker did make some changes in response to Jean's
issues, and the final result is probably better than either original
proposal.>>


This misremembers the history (as you will remember, I was very much
involved in this discussion). I am not sure whether Robert was present

at all the DR meetings that lead up to this, I think not ...


The initial issue was Jean's concern that "tagged" is a strange word
and that we should use "class" instead. This was really as much a concern
about using familiar terminology, rather than any purely technical concerns.
Indeed from a purely technical point of view, avoiding class, with its
baggage from C++ has some advantages. Tuck strongly opposed this change,
focussing purely on the technical aspects.

The DR's overwhelmingly agreed, and voted by a large margin to make the
change, despite Tuck's objections.

BUT, and this is a big BUT, they did NOT agree on a syntax. Jean wanted

   class type x is ...

but even some of those strongly supporting the idea of changing the
word were opposed to this prefix notation, and the issue of what syntax
to use was left open.

So the DR decision was clear: change tagged to class, and look for a
good syntax.

And we left the matter up to Salem (where Robert Eachus was present).

At Salem, Tuck gave a long and impassioned defence of tagged, and
Jean gave a long and impassioned argument for not just class, but
class AND the prefix syntax above.

This was of course a serious tactical mistake, but Jean felt he was
right, and insisted on presenting these together.

Mostly, the delegations were annoyed by the huge amount of effort
that had been spent on this relatively unimportant (as they saw it)
issue, especi9ally by the mapping team, and that mostly explains
the large number of abstentions (the vote was 2-2-4). However, it
did not entirely explain the abstentions.

At least one delegation in particular *strongly* favored class over
tagged, but did not like the prefix notation. They reacted by abstaining,
hoping that we could still get class without the prefix notation. That
was of coruse a tactical error on their part, the proper thing to achieve
their aim would be to have followed along with the proposal, and then look
for a better syntax in the aftermath. It is clear that if the vote had
been taken again with a bit better understanding, that this delegation
would have voted yes, giving 3-2-3.

The US delegation abstained, on the grounds that this was the best
syntehsis of the opinions of the design team (and Tuck), and other
members of the US delegation who strongly favored changing tagged
to class. I was the one who suggested that we join the winning side,
which ever it was, on the grounds that either way, the best thing was
to have a clear as possible decision.

Since this was a vote to CHANGE something, a tie fails, and consequently
the US delegation voted against to make this decision clear.

Many people still feel this decision was a mistake. Tagged is an odd word,
and it is awkward when people ask if Ada has classes to have to mumble a
bit. But in retrospect it is relatively unimportant, and I ssympathize
with the delegations who abstained because they felt too much fuss was
being made over a minor issue (incidentally, I am not guessing at this
dynamic, several people got up after the vote to present rather angry
opinions that we were wasting a lot of time on a trivial issue).

This was indeed one of the more contentious points in the history of the
development of the Ada 95 design -- any language design goes through
debates of this kind. What is remarkable is that the final result in the
Ada 95 case was that the standard was approved unanimously (by the
delegations that had been involved in the discussions, I believe there
were a couple of abstentions from official members who had never been
heard from or seen).

To me that is a significant achievment. Yes, we had lots of disagreements
as we went along, not the least of which was the fundamental tension between
trying to keep the changes small and managable from an implementation
point of view, and adding all sorts of wonderful features. But in the end,
we syntehsized a result that all of us were comfortable with.

To me, this was technical discussion and cooperation working in the best
possible way. Lots of different opinions, but everyone listening to
everyone else, and working hard together to take the best of everyones
input.

Robert Dewar