Re: Idea for Ada 200x: Arguments that are procedures

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

Steve says

<<I couldn't find the old discussions of this particular issue in the
Mapping / Revision Team stuff, or the Language Study Notes.  However,
if there was no better reason for keeping this feature out of the
language than that implementations using displays would have problems,
I think this "fix" absolutely should make it into Ada200x.
>>

There clearly will not be an anaologous development effort for Ada 200x
(compared to Ada 9X). FOr one thing the multi-million dollar funding
ncessary for such an approach is not there, and second, I don't think
anyone thinks it is appropriate at this stage.

Instead we can expect to see implementations introduce extensions that
are genuinely useful for Ada users on a gradual basis, and if and when it
is time for a new standard, it is more likely to be a ratification and
refinement of such existing extensions.

For example, the Size attribute, *particularly* in Ada 95, where the
situation has got worse due to some (in my opinion) injudicious choices
to be incompatible with most existing Ada 83 implementations, obviously
needs work. The Object_Size and Value_Size attributes in GNAT are 
essentially a proprosal in the direction of fixing this. Perhaps this
is not the best solution, but experimentation of this type is clearly
the right way to go in terms of implementing new features.

Of course this will tend to be driven by large serious users of Ada, but
that is as it should be. There are as in any language design a large
diverse collection of ideas from language enthusiasts (for example, there
are some who would go FAR beyond the limited access proposal, and insist
on full closures), but real users doing real applications are always a
somewhat more credible source of input on what the real problems are!