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Diffstat (limited to 'src/gl/m4/bison.m4')
| -rw-r--r-- | src/gl/m4/bison.m4 | 92 |
1 files changed, 92 insertions, 0 deletions
diff --git a/src/gl/m4/bison.m4 b/src/gl/m4/bison.m4 new file mode 100644 index 0000000..0493587 --- /dev/null +++ b/src/gl/m4/bison.m4 @@ -0,0 +1,92 @@ +# serial 10 + +# Copyright (C) 2002-2006, 2008-2021 Free Software Foundation, Inc. +# This file is free software; the Free Software Foundation +# gives unlimited permission to copy and/or distribute it, +# with or without modifications, as long as this notice is preserved. + +# There are two types of parser skeletons: +# +# * Those that can be used with any Yacc implementation, including bison. +# For these, in the configure.ac, up to Autoconf 2.69, you could use +# AC_PROG_YACC +# In newer Autoconf versions, however, this macro is broken. See +# https://lists.gnu.org/archive/html/autoconf-patches/2013-03/msg00000.html +# https://lists.gnu.org/archive/html/bug-autoconf/2018-12/msg00001.html +# In the Makefile.am you could use +# $(SHELL) $(YLWRAP) $(srcdir)/foo.y \ +# y.tab.c foo.c \ +# y.tab.h foo.h \ +# y.output foo.output \ +# -- $(YACC) $(YFLAGS) $(AM_YFLAGS) +# or similar. +# +# * Those that make use of Bison extensions. For example, +# - %define api.pure requires bison 2.7 or newer, +# - %precedence requires bison 3.0 or newer. +# For these, in the configure.ac you will need an invocation of +# gl_PROG_BISON([VARIABLE], [MIN_BISON_VERSION]) +# Example: +# gl_PROG_BISON([PARSE_DATETIME_BISON], [2.4]) +# With this preparation, in the Makefile.am there are two ways to formulate +# the invocation. Both are direct, without use of 'ylwrap'. +# (a) You can invoke +# $(VARIABLE) -d $(SOME_BISON_OPTIONS) --output foo.c $(srcdir)/foo.y +# or similar. +# (b) If you want the invocation to honor an YFLAGS=... parameter passed to +# 'configure' or an YFLAGS environment variable present at 'configure' +# time, add an invocation of gl_BISON to the configure.ac, and write +# $(VARIABLE) -d $(YFLAGS) $(AM_YFLAGS) $(srcdir)/foo.y +# or similar. + +# This macro defines the autoconf variable VARIABLE to 'bison' if the specified +# minimum version of bison is found in $PATH, or to ':' otherwise. +AC_DEFUN([gl_PROG_BISON], +[ + AC_CHECK_PROGS([$1], [bison]) + if test -z "$[$1]"; then + ac_verc_fail=yes + else + cat >conftest.y <<_ACEOF +%require "$2" +%% +exp: +_ACEOF + AC_MSG_CHECKING([for bison $2 or newer]) + ac_prog_version=`$$1 --version 2>&1 | sed -n 's/^.*GNU Bison.* \([[0-9]]*\.[[0-9.]]*\).*$/\1/p'` + : ${ac_prog_version:='v. ?.??'} + if $$1 conftest.y -o conftest.c 2>/dev/null; then + ac_prog_version="$ac_prog_version, ok" + ac_verc_fail=no + else + ac_prog_version="$ac_prog_version, bad" + ac_verc_fail=yes + fi + rm -f conftest.y conftest.c + AC_MSG_RESULT([$ac_prog_version]) + fi + if test $ac_verc_fail = yes; then + [$1]=: + fi + AC_SUBST([$1]) +]) + +# This macro sets the autoconf variables YACC (for old-style yacc Makefile +# rules) and YFLAGS (to allow options to be passed as 'configure' time). +AC_DEFUN([gl_BISON], +[ + : ${YACC='bison -o y.tab.c'} +dnl +dnl Declaring YACC & YFLAGS precious will not be necessary after GNULIB +dnl requires an Autoconf greater than 2.59c, but it will probably still be +dnl useful to override the description of YACC in the --help output, re +dnl parse-datetime.y assuming 'bison -o y.tab.c'. + AC_ARG_VAR([YACC], +[The "Yet Another C Compiler" implementation to use. Defaults to +'bison -o y.tab.c'. Values other than 'bison -o y.tab.c' will most likely +break on most systems.])dnl + AC_ARG_VAR([YFLAGS], +[YFLAGS contains the list arguments that will be passed by default to Bison. +This script will default YFLAGS to the empty string to avoid a default value of +'-d' given by some make applications.])dnl +]) |