Re: Crosspost: Help wanted from comp.compilers

[Hyman Rosen <hyrosen@mail.com>]

Robert I. Eachus wrote:
> If you understood Ada, you would understand that all of the "evidence" 
> you supplied confirmes what we have said.  The issue going into the Ada 
> 9X process was that tools that tried to short-cut the Ada recompilation 
> rules were tried--and they were much worse than the problem.

If you go back to my original post, you'll see that I wrote
     the implementations were horrible, leading to frequent
     unnecessary "recompile the world" scenarios

How is that different from what you just said? Are you
disagreeing with me that this was the case?

 > Do you really understand how the GNAT "source based" model works?

Yes, in fact I do.

> Everytime...

As some of my evidence pointed out, the compilation systems which
caused problems appeared to use compilation timestamps in their
dependency checking, such that simply compiling a file caused the
system to consider it to be newer than its dependents, and thus led
to their recompilation in a days-long cascade. I don't know why
they did it that way, but it certainly seems clear that they did.
Certainly Ada doesn't require that this happen, which is why I
spoke about horrible implementations, not horrible Ada.

GNAT's way means that a file is recompiled only when the source
modules it depends on change.