/usr/share/doc/libparse-recdescent-perl/examples/demo_autorule.pl is in libparse-recdescent-perl 1.967013+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 | #!/usr/bin/perl -ws
# use strict;
use Parse::RecDescent;
print 1 if Parse::RecDescent->new(<<'EOGRAMMAR')->file(join "", <DATA>);
<autorule: /\w+/ { print "Found $item[-1]\n" } >
file: defn(s)
defn: 'def' ident ':' block
block: '{' item(s) '}'
EOGRAMMAR
__DATA__
def ident : { item item item }
|