On Wed, Apr 23, 2008 at 10:07:06PM -0400, Mike Mueller wrote: > I'm working on a project with a couple flex-generated lexers and an > automake/autoconf build system. I've noticed the following: > > Automake runs flex via ylwrap. ylwrap, according to the manual: > > A shell script used by an automake generated `Makefile' to run > programs like `bison', `yacc', `flex', and `lex'. These programs > default to producing output files with a fixed name, and the > `ylwrap' script runs them in a subdirectory to avoid file name > conflicts when using a parallel make program. > > However, I have a feeling this hasn't been true about flex for a long > time. Flex has options that are very useful, including one for > specifying an output file name (%option outfile="foo.cc"). > > A side-effect of running flex in a ylwrap jail is that I can't generate > a header file using automake's default .l-file handler. I specified the > option header-file="foo.h", but based on the description above, I'm > assuming the file is generated in a temporary subdirectory, and then > blasted by ylwrap. > > I'm going to have to hand-write my rule to build flex files, to be able > to use the most basic features of flex. Hopefully you guys can pull > flex out of the special category of programs that need ylwrapping, so > that in the future, people will be able to use flex more naturally.
It sounds like the new feature I was requesting would solve you problem. Basically, a way to tell automake that a particular input file, generates a few output source or header files. Then automake would automatically build those source/header files from the input file using the action that you gave it to do so. The action could be a simple shell script, or in your case, it would be 'flex foo.l'. Perhaps someone would agree with me... Thanks, Bob Rossi
