The recipe for genfiles basically does this

chdir to src
foreach basename of "*.pdl" files
    if( $basname.cxx does not exist )  or 
      ( $basname.pdl is newer than $basename.cxx )
    then
        execute NOIPGEN on $basename.pdl outputting 
        stderr and stdout to $OBJDIR/noipgen.err
    endif
endfor

if( $OBJDIR/noipgen.err exists )
then
    mv the noipgen.err file to noipgen.debug
endif

chdir to src
foreach basename of "*mdl" files
    if( $basname.cxx does not exist ) or 
      ( $basnemae.mdl is newer than $basname.cxx)
    then
      execute NOIMGEN on $basename.mdl outputting 
      stderr and stdout to $OBJEDIR/noimgen.err
    endif
endfor

if( $OBJDIR/noimgen.err exists )
then
    mv the noimgen.err file to noimgen.debug
endif
[download]

You could easily combine those two things into a perl script and then change the recipe to be something like this:

genfiles: setup
        @my_script pdl $NOIPGEN $OBJDIR noipgen.err
        @my_script mdl $NOIMGEN $OBJDIR noimgen.err
[download]

-derby

update but now that I think about it some more that whole script could be replaced by more generic makefiles recipes that show target files have a dependancies on pdl and mdl files. Check out the make book.

thanks derby :)

While I wouldn't want to rewrite a makefile in perl

How about rewriting make in Perl? :)

I beg to differ. cons is not Make. It's a make-like thing with a different basic philosophy. If you want Make in Perl, you would simply use pmake, which is a pure-Perl version that can understand normal Makefiles, including everything that ExtUtils::MakeMaker puts out.

-- Randal L. Schwartz, Perl hacker