[PPL-devel] Configure substitutions are not allowed in _SOURCES variables

[Ralf Wildenhues]

* Roberto Bagnara wrote on Thu, Aug 21, 2008 at 08:00:04PM CEST:
> Ralf Wildenhues wrote:
>>
>> Are you saying that you generate Makefile.am (or an include snippet
>> for it) automatically?

> no.  In the previous version we generated automatically the individual
> C++ sources, including one that #included all the others.  The list
> of C++ sources is only known at configure time: at that time the
> sources are generated.

Well, as long as the list of possible source can be enumerated, you can
use EXTRA_*_SOURCES to list them.

>> If not, why not, if yes, what is the problem
>> with maintaining consistency with a script?  Ideally, you generate
>> both the files and the makefile.am snippet from the same script.
>
> Can I generated the Makefile.am at configure time?

No.

> Notice that
> the list of domains is really unbounded: the PPL supports constructions
> on domains like products and powersets.  So the user can ask
> for a product of a powerset of a product of ...
> We really cannot anticipate all the possibilities.

That's a problem.

There *may* be a workaround.  Let's rather call it ugliest hack ever.
It *requires* that you don't use per-target flags.  It does not provide
dependency tracking for the generated files.

> I am halfway through it.  I thought I had found a workaround,
> but there are still problems.  What I have at the moment is
> something that suffers from the problem outlined above and,
> in addition, does not work:
[...]
> # @required_instantiations_prolog_cxx_objects@ contains
> # the list of the .lo file corresponding to the .cc files
> # above.  If I do `make libppl_swiprolog.la' I get
> # the error that the (inexistent) .lo files are invalid
> # Libtool files.  Bot if I do, e.g.,
> # `make pl_prolog_Polyhedron.lo' the right thing happens.
> # I wonder why `make libppl_swiprolog.la' does not make
> # all the required .lo files.

Yep.  Your approach is essentially the hack I had in mind.
Put the added objects in libppl_swiprolog_la_DEPENDENCIES,
too, then things will work.  Of course then you have to
put everything else manually in that DEPENDENCIES variable,
too (which automake would otherwise do).

Cheers,
Ralf