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

[Dan Manthey]

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
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.

> > 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.

> 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.

> I think that provided the AS_MSG_END macro produces a clear message
> with dependency information when configure is run, and does so at
> the end as you say, this would be a very significant improvement.
> >
> > I'm not convinced that the dependencies are complex enough to need
> > anything more than sane use of if-else, but in the few cases where it is,
> > 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.

> #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.

> 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