\N{...} is already a recognized pattern in perl5 regexp language. Pick something else and add it to your current perl using the instructions at Extending Regular Expression Syntax. It's a presentation I gave to Minneapolis.pm last year. Or... co-opt \N for your own use. It isn't as if \N is so common that you'd miss it if you stole it away from perl. In my demo I redefined \w and \b to something more appropriate for my own set of common tasks.