+AT_CHECK([$PERL -w ./gengram.pl $2 || exit 77], 0, [stdout])
+mv stdout $1
+AT_BISON_OPTION_POPDEFS
+])
+
+
+## ---------------- ##
+## Big horizontal. ##
+## ---------------- ##
+
+AT_SETUP([Big horizontal])
+
+# I have been able to go up to 10000 on my machine, but I had to
+# increase the maximum stack size (* 100). It gave:
+#
+# input.y 263k
+# input.tab.c 1.3M
+# input 453k
+#
+# gengram.pl 10000 0.70s user 0.01s sys 99% cpu 0.711 total
+# bison input.y 730.56s user 0.53s sys 99% cpu 12:12.34 total
+# gcc -Wall input.tab.c -o input 5.81s user 0.20s sys 100% cpu 6.01 total
+# ./input 0.00s user 0.01s sys 108% cpu 0.01 total
+#
+AT_DATA_HORIZONTAL_GRAMMAR([input.y], [1000])
+
+# GNU m4 requires about 70 MiB for this test on a 32-bit host.
+# Ask for 200 MiB, which should be plenty even on a 64-bit host.
+AT_INCREASE_DATA_SIZE(204000)
+
+AT_BISON_CHECK_NO_XML([-v -o input.c input.y])
+AT_COMPILE([input])
+AT_PARSER_CHECK([./input])
+
+AT_CLEANUP
+
+
+
+# AT_DATA_LOOKAHEAD_TOKENS_GRAMMAR(FILE-NAME, SIZE)
+# --------------------------------------------------
+# Create FILE-NAME, containing a self checking parser for a grammar
+# requiring SIZE lookahead tokens.
+m4_define([AT_DATA_LOOKAHEAD_TOKENS_GRAMMAR],
+[AT_BISON_OPTION_PUSHDEFS
+AT_DATA([[gengram.pl]],
+[[#! /usr/bin/perl -w
+
+use strict;
+use Text::Wrap;
+my $max = $ARGV[0] || 10;
+
+print <<EOF;
+%error-verbose
+%debug
+%{
+]AT_DATA_SOURCE_PROLOGUE[
+# include <stdio.h>
+# include <stdlib.h>
+# include <assert.h>
+# define MAX $max
+]AT_YYLEX_DECLARE[
+]AT_YYERROR_DECLARE[
+%}
+%union