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From: Robert A Duff <bobduff@shell01.TheWorld.com>
Newsgroups: comp.lang.ada
Subject: Re: Structured exception information
Date: Mon, 15 Jan 2007 17:32:37 -0500
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Date: 2007-01-15T17:32:37-05:00
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"Randy Brukardt" <randy@rrsoftware.com> writes:

> We did look at this issue when working on the Amendment. The "obvious"
> answers seem to have issues with visibility and compatibility with existing
> Ada.Exceptions mechanisms.

If we had done it right in Ada 95, we wouldn't have had the
Ada.Exceptions kludge in the first place, so no need to be complatible
with it.

I don't know what the visibility issues were, so I can't comment on
that.  Do you happen to know which AI this was?

Rant:

The attitude about this feature during Ada 9X seemed to be:

    1. Folks should not overuse exceptions.  (I agree.)

    2. Therefore, we should make exceptions painful to use.  (Sorry,
       that does not follow.)

The problem with (2) is: what about the cases where exceptions ARE
appropriate?  Pushing people in the direction of encoding information
un-type-safely as Strings, or using global variables, or whatever is not
helpful.  It's like removing the guard rail from a dangerous curve in
order to make drivers slow down.

The language designer should alway assume that programmers are competent
-- in this case, that they can decide whether exceptions are appropriate
in any given case -- and not try to prevent people from doing bad
things.  (Preventing people from doing bad things by accident, however,
is Good Language Design.)

- Bob