Hello --

You can (I think) test if some attribute value is an RFC 4122 UUID by using a regular expression:

let $regexp as xs:string := '^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-5][0-9a-fA-F]{3}-[089abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}$'

for $uuid in //@GUID
  let $value as xs:string := $uuid/string()
  where not(matches($value,$regexp))
  return $value

Is there a better way to do this?

thanks!

Graydon