Re: compilation cascades and new Fortran features

In article <1128063375.255265.308390@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
robert.corbett@xxxxxxx wrote:

> It is not just a matter of doing something incorrect. A user
> might, for example, want to update a comment in the file
> containing the specification part of a module.

And this is nothing unique to modules or even to Fortran. That is an
inherent "feature" of make in that it is based solely on file
modification times. In pretty much any kind of file that might be
involved in any language, you might have the same phenomenon of wanting
to update a comment and thus causing spurious recompilations. I could
spend a long time railing about the deficiencies of make, but that would
be both pointless and off-topic.

The design of modules in f90/f2003 is particularly prone to causing
spurious compilation cascades with make. That certainly sounded like
what the OP was asking about. I stick with my original comment that the
modules TR specifically addresses the question that the OP asked about.
It does not change the fundamental nature of make. It does, however,
specifically address the issue that modules caused worse problems with
make cascades than did other mechanisms.

This does not mean that you can't get compilation cascades. That is
fundamental to make. It doesn't mean that you can't get spurious ones.
That is just about as fundamental to make. It doesn't solve the inherent
issues (which you raised) of wanting compilation to be both separate and
inlined. (I have heard of schemes to address that by having the compiler
actually making both versions, but that seems to have nothing in
particular to do with either make or modules, as it comes up in
non-module cases without using make). The TR also doesn't solve world
hunger, in case anyone wondered. But I didn't see all those questions in
the OP's posting.

--
Richard Maine | Good judgment comes from experience;
email: my first.last at org.domain | experience comes from bad judgment.
org: nasa, domain: gov | -- Mark Twain
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