+
+# 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_CHECK([bison -v -o input.c input.y])
+AT_COMPILE([input])
+AT_PARSER_CHECK([./input])
+
+AT_CLEANUP
+
+
+
+# AT_DATA_LOOKAHEADS_GRAMMAR(FILE-NAME, SIZE)
+# -------------------------------------------
+# Create FILE-NAME, containing a self checking parser for a grammar
+# requiring SIZE lookaheads.
+m4_define([AT_DATA_LOOKAHEADS_GRAMMAR],
+[AT_DATA([[gengram.pl]],
+[[#! /usr/bin/perl -w
+
+use strict;
+use Text::Wrap;
+my $max = $ARGV[0] || 10;
+
+print <<EOF;
+%{
+#include <stdio.h>
+#include <stdlib.h>
+
+#define YYERROR_VERBOSE 1
+#define YYDEBUG 1
+
+static int yylex (void);
+static void yyerror (const char *msg);
+%}
+%union
+{
+ int val;
+};
+
+%type <val> input exp
+%token token
+EOF
+
+print
+ wrap ("%type <val> ",
+ " ",
+ map { "n$_" } (1 .. $max)),
+ "\n";
+
+for my $count (1 .. $max)
+ {
+ print "%token t$count $count \"$count\"\n";
+ };
+
+print <<EOF;
+%%
+input:
+ exp { if (\@S|@1 != 1) abort (); \$\$ = \@S|@1; }
+| input exp { if (\@S|@2 != \@S|@1 + 1) abort (); \$\$ = \@S|@2; }
+;
+
+exp:
+ n1 "1" { if (\@S|@1 != 1) abort (); }
+EOF
+
+for my $count (2 .. $max)
+ {
+ print "| n$count \"$count\" { if (\@S|@1 != $count) abort (); }\n";
+ };
+print ";\n";
+
+for my $count (1 .. $max)
+ {
+ print "n$count: token { \$\$ = $count; };\n";
+ };
+
+print <<EOF;
+%%
+static int
+yylex (void)
+{
+ static int return_token = 1;
+ static int counter = 1;
+ if (counter > $max)
+ return 0;
+ if (return_token)
+ {
+ return_token = 0;
+ return token;
+ }
+ return_token = 1;
+ return counter++;
+}
+
+static void
+yyerror (const char *msg)
+{
+ fprintf (stderr, "%s\\n", msg);
+}
+
+int
+main (void)
+{
+ yydebug = !!getenv ("YYDEBUG");
+ return yyparse ();
+}
+EOF
+]])
+
+AT_CHECK([perl -w ./gengram.pl $2 || exit 77], 0, [stdout])
+mv stdout $1
+])
+
+
+## ----------------- ##
+## Many lookaheads. ##
+## ----------------- ##
+
+AT_SETUP([Many lookaheads])
+
+AT_DATA_LOOKAHEADS_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_CHECK([bison -v -o input.c input.y])
+AT_COMPILE([input])
+AT_PARSER_CHECK([./input])