Re: [Bug-gnulib] AC_PROG_YACC

[Bruno Haible]

Mark D. Baushke wrote:
> I will also note that the current getdate.y assumes that a bison 1.35 or
> more recent is available.

OK, can we then replace gnulib's bison macro with the following:

AC_DEFUN([gl_BISON],
[
  # getdate.y works with bison only (because it uses bison specific features)
  # and actually requires bison >= 1.26.
  # bison is only needed for the maintainer (who touches getdate.y). But in
  # order to avoid separate Makefiles or --enable-maintainer-mode, we put
  # the rule in general Makefile. Now, some people carelessly touch the
  # files or have a broken "make" program, hence the getdate.c rule will
  # sometimes fire. To avoid an error, define GL_BISON to ":" if it is not
  # present or too old.
  AC_CHECK_PROGS([GL_BISON], [bison])
  if test -z "$GL_BISON"; then
    ac_verc_fail=yes
  else
    dnl Found it, now check the version.
    AC_MSG_CHECKING([version of bison])
changequote(<<,>>)dnl
    ac_prog_version=`$GL_BISON --version 2>&1 | sed -n 's/^.*GNU Bison.* 
\([0-9]*\.[0-9.]*\).*$/\1/p'`
    case $ac_prog_version in
      '') ac_prog_version="v. ?.??, bad"; ac_verc_fail=yes;;
      1.2[6-9]* | 1.[3-9][0-9]* | [2-9].*)
changequote([,])dnl
         ac_prog_version="$ac_prog_version, ok"; ac_verc_fail=no;;
      *) ac_prog_version="$ac_prog_version, bad"; ac_verc_fail=yes;;
    esac
    AC_MSG_RESULT([$ac_prog_version])
  fi
  if test $ac_verc_fail = yes; then
    GL_BISON=:
  fi
  YACC="$GL_BISON -y"
  AC_SUBST(YACC)
])

Bruno