Re: Integrating flexc++(1) and bisonc++(1) into Makefile.am

[Kip Warner]

On Wed, 2017-07-12 at 10:23 -0400, Nick Bowler wrote:
> Hello,

Hey Nick.

> There aren't really any "elegant" solutions.  Make handles this kind
> of tool quite badly.  It is possible to get things to work but it is
> always a tradeoff between flexibility of your build system and
> simplicity of your rules.

I had suspected something along those lines due to the scarcity of
documentation that's well defined on this particular class of problem,
but feel better knowing my hack might be close to as good as it's going
to get for the time being.

> If you are happy with this method then it is totally fine.  Do make
> sure parallel builds work by testing them routinely (both clean and
> incrementally) -- I think listing everything in BUILT_SOURCES like
> you do probably "resolves" any parallelism problems here, (by
> reducing opportunities for parallelism).

Tested. It appears to work fine. Everything else will presumably be
able to build in parallel, but the flexc++(1) and bisonc++(1) derived
targets will have to be in serial.

> The Automake manual has section on writing portable make rules for
> tools that produce multiple outputs[1], with a discussion of various
> approaches and their limitations.  I generally prefer approaches
> using a dedicated witness file.

I took a look at this and I think it's a good idea. But I also think
that it may not be worth it if I have to integrate these two tools in
only one place in the build environment, as opposed to with multiple
parsers in multiple sub projects or some such.

> Finally, consider whether you want to distribute the generated parser
> sources.  That way your users don't need these tools installed just
> to build your package.

I think that as long as I don't have to actually modify the generated
parser sources, I don't have a problem requiring the user to have the
two tools installed. Most of the compilation I'll be doing, and most of
what remains will probably be on a build server which will
automatically pull the required build dependencies (e.g. sbuild debs).

Thanks a lot for your help, Nick.

-- 
Kip Warner | Senior Software Engineer
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http://www.thevertigo.com

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