Re: Attributes 'Version and 'Body_Version

[dewar@gnat.com (Robert Dewar)]

Kilgallen@SpamCop.net (Larry Kilgallen) wrote in message news:<PFcoNrf74AeG@eisner.encompasserve.org>...
> But going to a newer version of the same vendor's 
> compiler
> is something programmers expect to be effortless.  If
> that vendor implements a new language-defined attribute
> rather than its former implementation-defined attribute
> which had the same name, the expectation might not be
> realized.

If they expect this for going from a vendors compiler for
one Ada standard to its successor, they are fooling themselves. Easy
yes, effortless no. I remember the project
manager for the old ATC system saying that she expected
to be able to move from Ada 83 to Ada 95 without changing
a single character of source and I shook my head ...
 

> The sort of approach I would have expected would be a
> division of the namespace.  VMS linker (and other) 
> namespace
> segregation is done with a dollar sign.  Not that a 
> dollar
> sign is appropriate for Ada, but I would expect some area
> set aside into which the language-defined attributes will
> not trespass in the future.

Why?
This has not been a problem in practice.
Why solve problems that do not exist, when the result would
be to degrade readability. 

It is really useful that the assert pragma in GNAT has this
name and not something like Implementation_Assert or somesuch junk. 

If there is an Ada 0x, and if it includes Assert, and if
it (surprisingly) is not upwards compatible with the GNAT
pragma, then it is annoying but not disastrous to have to
run a trivial script to change the name of pragma Asserts.