This is a proposal for a versatile, multi-dimensional classification scheme for use cases on behalf of REWERSE.
The proposed classification dimensions are: 'application field', 'type of rules', 'type of data accessed', 'type of data generated', 'relationship to query language(s)'. In more details:
1. 'application field': standard web, semantic web, web services, trust negociation, business process modeling, contextualization/personalization, other.
2. 'type of rules': normative rules (or structural rules, or integrity constraints), deductive rules (or deduction rules or database views or constructive rules), active (or reactive rules). (These three kinds of rules are briefly discussed at Classification of Rules and in this paper.
3. 'types of data accessed' (ie data "queried" in rule bodies): XML/HTML, RDF, Topic Maps, OWL.
4. 'types of data generated' (ie data "constructed" in rule heads): XML/HTML, RDF, Topic Maps, OWL.
5. 'truth values': false/true, discrete set (e.g. false/unknown/true or known-false/assumed-false/assumed-true/known-true), continous set (eg [0, 1]).
6. 'relationship to query language(s)':
6.1 query language(s) that can be used for accessing data (i.e. query languages that can be called in rule bodies).
6.2 kinds of calls to query language: procedural attachement vs. variable/variable binding interface (as e.g. in: p(X,Y) & Y from 'xquery-program' & q(Y, Z)).
A good classification is important for ensuring all use cases being considered.
Impact on Design
This WG already has a rich set of different and complementary use cases. They are all essential for demonstrating the importance/relevance of a Rule Interchange Format.