PQN - is there a formal grammar? Does it support V3

I found a reference to PQN in the Z39.50 URL RFC. I believe PQN came
originally from YAZ(?). I gave a new programmer an exercise of having
a go at turning RPN into PQN (to introduce them to Z39.50). But they
came up with some constructs that were possible in RPN but not PQN
from first glance. Eg: V3 allows an attribute set per attribute type/value.

Is there a better or more modern definition of PQN that handles all
of V3 RPN?

Thanks!
Alan
-- 
Alan Kent (mailto:ajk@mds.rmit.edu.au, http://www.mds.rmit.edu.au/~ajk/)
Postal: Multimedia Database Systems, RMIT, GPO Box 2476V, Melbourne 3001.
Where: RMIT MDS, Bld 91, Level 3, 110 Victoria St, Carlton 3053, VIC Australia.
Phone: +61 3 9925 4114  Reception: +61 3 9925 4099  Fax: +61 3 9925 4098

Received on Wednesday, 17 April 2002 21:31:49 UTC