Re: Crosspost: Help wanted from comp.compilers

["John R. Strohm" <strohm@airmail.net>]

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"Hyman Rosen" <hyrosen@mail.com> wrote in message
news:3b1Ta.14846$0F4.12183@nwrdny02.gnilink.net...
> Robert I. Eachus wrote:
> > If your main program is A from above, and you recompile B, the
> > implementation has two choices.  It can leave the original compiled
> > version of B in the environment and link A and the old B, or it can tell
> > you to recompile A.
>
> I'm starting to remember an earlier discussion on this subject, (that
> I don't think I was involved in). If I recall correctly, it's valid to
> define "exist in the environment" as "source code is readable" and to
> define "compile" as "check that the code is legal". Then object file
> generation doesn't have to be tied to the requirements that you are
> talking about, so the issue can be sidestepped (while still remaining
> true to both the letter and spirit of the Ada requirements).

That is true, BUT it does not satisfy the critical requirement.

The critical requirement is not for "exist in the environment".

The critical requirement, as Robert pointed out, is for "consistency" at
link time.  This is what drives the recompilation rules.