CQL::Parser provides a mechanism to parse Common Query Language (CQL) 
statements. The best description of CQL comes from the CQL homepage at the 
Library of Congress http://www.loc.gov/z3950/agency/zing/cql/

CQL is a formal language for representing queries to information retrieval 
systems such as web indexes, bibliographic catalogs and museum collection 
information. The CQL design objective is that queries be human readable 
and human writable, and that the language be intuitive while maintaining 
the expressiveness of more complex languages.

A CQL statement can be as simple as a single keyword, or as complicated as 
a set of compoenents indicating search indexes, relations, relational 
modifiers, proximity clauses and boolean logic. CQL::Parser will parse CQL 
statements and return the root node for a tree of nodes which describes 
the CQL statement. This data structure can then be used by a client 
application to analyze the statement, and possibly turn it into a query 
for a local repository.

WWW: http://search.cpan.org/dist/CQL-Parser/
Authors:
    * Ed Summers - ehs at pobox dot com
    * Brian Cassidy - brian.cassidy at gmail dot com
    * Wilbert Hengst - W.Hengst at uva dot nl