Dive in to OCQL parser

I had a deep dive in to the OCQL(refer previous threads) parser. It is interesting to see how the program shift and reduce example queries according to the rules defined, by using debugging. Execution flow can be easily recognize form it.
I had to modify and add missing rules in the implementation. I spent whole the day for this part though it looks very simple took fairly large time. Since the parser implementation is not done by me, I initially I studied how the system works for a single running test. It helped me to understand the reasons for the failing tests. I really enjoyed with today's work and commit the work in the repository[1]

[1] svn://svn.zope.org/repos/main/Sandbox/adamg/ocql/branches/dbprovider