You might also have a look at the flex test suite to see various ways in which automake is abused to build odd things for flex itself. There's a lot of edge cases there and you might get ideas.
On Wednesday, 12 July 2017, 10:23 am -0400, Nick Bowler <nbow...@draconx.ca> wrote: > Hello, > > On 7/12/17, Kip Warner <k...@thevertigo.com> wrote: > > My challenge is replicating their functionality for flexc++(1) and > > bisonc++(1) in the absense of macros to make their usage easier in > > Automake > [...] > > In trying to integrate the two tools into my build environment, I've > > attempted the following in Makefile.am: > [...] > > BUILT_SOURCES = \ > [...] > > Source/ParserBase.h \ > > Source/Parser.h \ > > Source/Parser.ih \ > > Source/Parser.cpp > > > > myprogram_SOURCES = \ > [...] > > Source/Parser.cpp > [...] > > # Generate parser source from Backus-Naur grammar rules via bisonc++... > > Source/ParserBase.h: > > Source/Parser.h: > > Source/Parser.ih: > > Source/Parser.cpp: Source/Parser.ypp > > $(BISONCPP) --target-directory=$(top_builddir)/Source $< > > > > FLEXCPP and BISONCPP are obtained via AC_PATH_PROG in configure.ac. > > > > This all works ok, but I suspect this is not an elegant solution and > > there are some very good suggestions from this mailing list. > > 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. > > 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). > > 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. > > 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. > > [1] > https://www.gnu.org/software/automake/manual/automake.html#Multiple-Outputs > > Cheers, > Nick > -- Will Estes westes...@gmail.com
