Re: Ada Core Technologies and Ada95 Standards

[bobduff@world.std.com (Robert A Duff)]

In article <828474655.17825@assen.demon.co.uk>,
John McCabe <john@assen.demon.co.uk> wrote:
>Finally, the ESA rep has some very strange ideas about software and
>gets very confused.

Perhaps they're confused about the use of the term "proof".  ;-)

> We spend hours explaining things to him, and he
>seems to take it in, then he brings up exactly the same topic at the
>next meeting - even when the topic has nothing to do with software.
>It's very frustrating.

>We do this by using LDRA Testbed with limits on the minimum level of
>statement and branch coverage of 100%, and 70% on LCSJ's. I'm not sure
>exactly where those figures are derived from, but they seem
>reasonable. The only problem here is that we've found a few bugs in
>that tool as well!

Surely that's not the *only* problem.  Surely the test cases fail to
cover every combination of requirements, and therefore some bugs slip
through.

>If it's provides more coverage than the ACVC, why isn't it used
>instead, or alongside ACVC.

I don't think that the ACVC ever intended to eliminate all bugs from Ada
compilers.  It intends to prevent compilers that fail to implement whole
portions of the language, or implement extensions.  It does a pretty
good job of that, but could do better.  But the intent, I think, is that
Ada compiler vendors test their own products properly.  Whether they do
so or not is up to the marketplace.

>Going back to point 3, I get the impression that ACVC is inherently
>limited by its need to be applicable to all Ada compilers.

Yes.

>... Based on
>the methods you and I use, would it not be better to use the ACVC
>suite as a basis for the compiler vendors tests, and also require the
>compiler vendors to submit their own test suites for approval.

At least *some* of the compiler vendors' tests include proprietary code
from their customers, and they simply cannot release that code.

- Bob