Re: Standard Ada Preprocessor

[Jacob Sparre Andersen <sparre@nbi.dk>]

Warren W. Gay VE3WWG wrote:

> So the challenge is to use the best technology (Ada) and yet be
> capable of accomodating a large range of "environments".

Agreed.

But don't you agree that allowing a preprocessor to work on package
specifications isn't exactly good Ada style.  Then you can't trust the
package specifications anymore.  Although I prefer a simple "choose an
appropriate package body" method, I can see some benefits of allowing
full preprocessing of package bodies.

My main problem right now is: Is it possible to specify a sensible
common method for asking the compiler questions about the target
environment?  How?

My first thought was to tell the user (of the compiler) to give the
compiler some appropriate flags, indicating the information needed for
selecting which package bodies to choose.  But that would still leave
the problem of making those configuration decisions to the user
instead of automating them.

Could we ask the compilers to be able to tell us if some library (a
string indicating a library name) exists in a specific version (a
string indicating a version)?  What do compiler vendors say to that?

What other kinds of compile time switches do we want to be able to
make?  Either based on user choice or on the configuration of the
target system.

> I think because of the targeted end user, Open Sourced projects have
> a special "need", compared to perhaps the "typical" Ada project
> (whatever that is ;-)

Yes.  But users of Open Source software already seem to have agreed to
use Autoconf/Automake as their "standard" compile-time configuration
tool.  How does that work on non-Unix systems BTW?

> I never suggested that someone should just plop it into the ARG's
> lap without doing homework/whatever. All I can do is speak for
> myself here, and say that I just wanted to have an open discussion
> on the merits of some sort of conditional compilation.

Good.  Maybe we can actually come up with a suggestion we can sell to
the ARG.

> The result of this discussion seems to suggest that most are
> resisting the idea, for different reasons. So be it. Maybe with
> time, resistance to the idea will fade as more people try to address
> the practical problems that Open Sourced projects face in Ada. One
> can hope ;-)

I hope we can find a solution that makes it easier for people who
receive a source code package with an Ada program to just compile and
run the program, _without_ letting the whole C preprocessor hell loose
in Ada too.

Greetings,

Jacob
-- 
"Hungh. You see! More bear. Yellow snow is always dead give-away."