category codes and regexps

[Werner LEMBERG]

Assume that I want to check a buffer for characters which aren't Thai,
and which aren't in the range a-z.  My first idea was this:

  [^\cta-z]

This fails because `\' isn't special within [...].  What's the correct
(interactive) way to do that?  I tried hard without finding a regexp
which can handle this.


    Werner