Evaluate new AttributeType (eg, "Guid") to replace repetetetive identical definitions of the GUID strict RegEx pattern

[Erik0x42]

Is it possible to define the GUID RegEx pattern once - in a type - and then use the type where needed, instead of re-defining the GUID pattern everywhere?

Ref. repeated occurrences of:

        <Constraint Name="aml-RegExp">
          <UnknownType>
            <Requirements>^[0-9A-Fa-f]{8}(-[0-9A-Fa-f]{4}){4}[0-9A-Fa-f]{8}$</Requirements>
          </UnknownType>
        </Constraint>

The question was originally asked in pull request #50 (this issue created to track the follow-up).