Re: RFE: configure -> dependency list on exit.

[Hugh Sasse Staff Elec Eng]

On Thu, 24 Feb 2005, Dan Manthey wrote:

> On Thu, 24 Feb 2005, Hugh Sasse Staff Elec Eng wrote:
>
> > On Thu, 24 Feb 2005, Dan Manthey wrote:
> >
> > >  AC_MSG_END([A lexer is needed for yacc.]
> > > AS_PACKAGE_SUGGEST([flex 2.5.x],[http://gnu.org/whereever_flex_is.html])
> > > AS_PACKAGE_SUGGEST([lex]))
> >
> >          [OT] I don't understand this extra ')' but ...
>
>         Closes the one opening AC_MSG_END.  The formatted result output by

Oh!  My eyesight caught me out there I think!  Thanks.

> AS_PACKAGE_SUGGEST is part of what to report at the end of the configure
> run.
>
> > I like this, it is clear.  Could the shell logic be produced by a
> > Macro, though, to help people get it right?
>
>         Actually, we've already got AS_IF (That's (A) for Autoconf and (S)
> for shell, not "as _if_!  duh!".), but using that may conflict with part

        :-)

> of the proposal for conditional macros; don't know yet.

OK.
> > > file which is later output), and possibly AS_PACKAGE_SUGGEST, a fascility
> > > quite orthogonal to the logic that determines which tests are run.  It
> > > would have the job of appropriately describing a recommended place to get
> > > a package.  This could (possibly) do anything from simple string
> > > formatting to some sort of database lookup.
> >
> > Yes, that would be a good addition, though I think it will meet
> > resistance because of the documentation overhead.  Anwyway, having
> > it as a standard macro allows future flexibility, such as the Free
> > Software Directory adopting GNOWSYS or enquiring of some future vast
> > artificial intelligence :-).
>
>         Frankly, I think I'd resist it, but it seemed to be what you were
> asking for.

Well, the rejection of this would be reasonable as it opens a whole
new can of worms, but it would probably be worth trying to get some
concensus about it.  I won't be mortified if it doesn't get through.
> > I don't think we need to generate a DEPENDENCIES file, although it
> > would be nice to generate supporting documentation automatically.
>
>         Here I have to side with Paul and ask exactly what you mean by
> that.

It might be possible -- note: not an immediate goal -- to turn the
static declarations of dependency into a text file for end users to
read.  But the important thing is the AS_MSG_END facility, and the
the conditional branching on tests.  If there are no generated docs
I'd still be pleased (and someone else may revisit the issue later,
anyway). The information determined by what is on the system is
more useful, as it doesn't contain things people would rather not
read.
>
        [...]
> > > that can be expressed with the form of AC_REQUIRE that takes code to
> > > execute as well as an identifier to have provided:
> > >
> > > AC_DEFUN([AC_PROG_YACC_THAT_NEEDS_LEX],
> > > [AC_REQUIRE([_YACC_CHECK_LEX],
> > > [AC_PROG_LEX
> > > if test $LEX = :; then
> > > AC_MSG_END([Yacc needs lex])
> > > fi])
> > > if test $LEX != :; then
> > >  AC_PROG_YACC
> > > fi])
> >
> > If the case for a failure is always a : (nicely a NO-OP in ksh at
>
>         Sadly, no.  That's the particular behavior of AC_PROG_LEX.  I
> would presume that it's so that future calls of `$LEX foo.l' don't puke.
>
> > least, and, it seems, bash) then there is scope for something like
>
>         Yes, : is the sh-standard no-op.

I think I had it fail in Sun's sh a while back. But I digress.
> > #define  AC_IF_FAILED(LEX) if test $LEX != :; then
> > #define  AC_ELSE_FAILED(LEX) else
> > #define  AC_END_FAILED(LEX) fi
>
>         No no no no, that's hideous.
>         AS_IF([test $LEX != :],true-case,false-case)
>         You need to have the caller specify `test' so they can use other
> tests, too, e.g. grep a file.

OK, I'd be happy with that.  There's nothing more one can factor
out, so I agree.
> > Thank you.  I think you have cut through a lot of the confusion that
> > was springing up.  I like it when people manage to simplify things
> > so neatly.
>
>         Well, let's see if it helped Paul at all.
>
> -Dan

        Hugh