/usr/share/doc/libparse-recdescent-perl/examples/demo_matchrule.pl is in libparse-recdescent-perl 1.967009+dfsg-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 | #!/usr/bin/perl -sw
use vars qw($animal);
use Parse::RecDescent;
$grammar = q {
object: thing[article=>'a'](s)
| thing[article=>'the'](s)
thing: <matchrule:$arg{article}>
<matchrule:${\scalar reverse $::animal}>
a: 'a'
the: 'the'
cat: 'cat' { print "meow\n"; $::animal = 'god' }
dog: 'dog' { print "woof\n" }
};
unless( $parser = new Parse::RecDescent( $grammar ))
{
die "bad grammar; bailing\n";
}
$/ = "";
while (defined ($input = <DATA>))
{
$::animal = reverse 'cat';
print STDERR "parsing...\n";
unless( defined $parser->object( $input ))
{
die "error in input; bailing\n";
}
print STDERR "...parsed\n";
}
__DATA__
a cat
a cat
a cat
a dog
the cat
the dog
the dog
the dog
the dog
a dog
|