Re: Rational for not making cursor tagged in Containers

[Robert A Duff <bobduff@shell01.TheWorld.com>]

"Randy Brukardt" <randy@rrsoftware.com> writes:

> "Robert A Duff" <bobduff@shell01.TheWorld.com> wrote in message
> news:wccbqhizsh0.fsf@shell01.TheWorld.com...
> ...
>> I also thought (and continue to think) that array types should be
>> allowed to have discriminants.  The quote above was a jab at people
>> who thought otherwise.  I lost that argument.
>
> That would have been me. I think I was arguing simply from the
> implementation complexity standpoint

Implementation complexity for existing (Ada 83) implementations.
A newly-designed implementation would have had no trouble.
20-20 hindsight!

I claim that it's much easier to implement Ada 95 than it is to
implement Ada 83 and then adapt that implementation to Ada 95.

The same applies to 95/2005.  I sweated blood implementing the AI-318
features (limited constructor functions) for Ada 2005 in GNAT, but I'm
pretty sure that AI-318 would be no extra trouble in a from-scratch
implementation of Ada 2005.

>... (my comment to Dmitry about the amount
> of code needed to implement parameter passing would be a lot worse with this
> capability). I think your argument was that such things should just be
> implemented as records, but that leads to the explosion of possibilities
> (now every array might be implemented in a number of new ways on top of the
> old ways). I'm not sure I'd make that argument again. (I know I wouldn't be
> against 'in out' parameters in functions again. The use of access types to
> replace them is disgusting.)

Agreed.

- Bob