Several versions
were made of the program but there are two main versions:
1)This first version has a rather classic
structure (Prolog-like) and was thouroughly tested using the testcases of De
Roo.
2)The second version has a structure that is
better adapted to the needs of the Semantic Web; it is more modular; it can
perform subqueries and respond to subqueries what makes it suited for a
client-server configuration. It it is extensible (builtins i.e. extra
functions like e.g. print or math functions can be added). It uses a
hashtable for storing the RDF triples so that all triples that match with a
certain goal can be retrieved at once.