#!/usr/bin/perl -wl

use strict;
use re "eval";

my @array = (
   [ 'a', 'b', 'c' ],
   [ 1, 2 ],
   ['x', 'y', 'z'],
   [7, 8, 9]
);
my $re;

map {
    $re .= "(\n".
        '((?{$^R."' . join('"})|(?{$^R."', @$_) . qq'"}))\n';
} @array;
$re .= ")?" x @array;
$re .= '(?{ push @_, $^R })(?!)';

print $re;
''=~/$re/x;
print for(grep defined($_), @_);

__END__