The BNF is reproduced for indicate the extensions are highlighted with bold characters. The original BNF was extended thinking in SQL where expression. Moreover, we found some errors in the specification and we have done corrections, that will help to use and analyse the CQL language.
 between predicate is extension *)
 TODO RELATE this require a new filter.
 bbox is an extension *)
This diagram presents the interface of module. In its protocolo parser method does the parsing of CQL and build the the filter.
The figura shows the principal class in the parser and build process. CQLParser does a top down analysis of the input string and makes the parsing tree using the SimpleNode class. Each time CQLParser build a node call to CQLCompiler, that implements the semantic actions relates and builds the product or subproduct required to make the Filter at final of parsing process