Regular expressions
In OCL, a regular expression match could be performed using regExpMatch, which will return true/false.
The following example shows one way to decide whether a string is a valid email address or not.
'åke.öberg@mdriven.se'.regExpMatch('^[a-öA-Ö0-9+_.-]+@[a-öA-Ö0-9.-]+\.[a-zA-Z]{2,3}$')