variable inside it's own allowed?

Hi,

Am i allowed to use a construction like this

  comment    = "\($ws($ctext|$quoted_pair|$comment)+$ws\)"

where this is the first time i define $comment?

        -Rejo.

-- 
= Rejo Zenger  [Sister Ray Crisiscentrum]               
rejo(_at_)sisterray(_dot_)xs4all(_dot_)nl
= http://mediaport.org/~sister                                  PGP: see headers
--------------------------------------------------------------------------------