Proposed regular expression for parsing XRIs

Appendix B of RFC 2396 provides a regular expression for parsing URIs. It
doesn't work for XRIs because we don't start with a // yet we still have an
authority component. Here's a stab at a regular expression that will parse
XRIs.

^((xri):)?((/{2}|@|=|\+|\*|\()([^/?#]*))?([^?#]*)(\?([^#]*))?(#(.*))?

I've attached a simple perl script you can use for testing.
I haven't exercised this very much, so it probably needs some tweaks. If
anyone's motivated, give it a try and let me know what valid XRIs it fails
on.

Dave