Re: Elaboration in GNAT

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

dewar@gnat.com (Robert Dewar) writes:

> 4. If you are working with legacy code, which has complex
> elaboration requirements, it is *highly* likely that the'
> code has serious bugs in it -- namely it does not have all
> the pragma Elaborate statements that should be there.

True, but is it not also the case that these bugs are relatively
innocuous?  That is, if you forget your pragmas, then your program
usually blows up during elaboration (and you fix it), or else it doesn't
blow up (using this compiler).  That is, it's more of a *portability*
problem, than a problem of programs malfunctioning when users use them.

It sure is frustrating when you have to fiddle with those stupid
pragmas, but that is surely less costly than "real" bugs -- the ones
that find their way into the hands of your program's users.

Ideally, all elaboration problems would be detected at compile time (or
link time), and there would be no constraints on the structure of a
program due to elaboration-order issues.  Ada (even with GNAT's default
mode) does not achieve that, unfortunately.

- Bob