<notAllowed/> as a name class

Before <except> was introduced, we can write a name class that accepts
nothing as

<not>
  <anyName/>
</not>

which is a short hand for

<difference>
  <anyName/>
  <anyName/>
</difference>


But I found that we now need to write the same name class as

<anyName>
  <except>
    <anyName/>
  </except>
</anyName>

and this is prohibited (because it's silly) if I'm correct.
This breaks the boolean closure of the name class and therefore I want
to fix it.


So I'd like to propose to add <notAllowed/> as a member of the name
class.

How do others think?



regards,
--
Kohsuke KAWAGUCHI                          +1 650 786 0721
Sun Microsystems