The condition sublanguage of RIF-BLD is intended to be a common basis for the dialects of RIF. First of all, it is used by RIF-BLD itself. Future dialects or groups of dialects where the Condition Language or its extensions might be used include:
Rule bodies and queries in declarative logic programming dialects (LP)
Rule bodies in first-order dialects (FO)
Conditions in the rule bodies of the Production Rule Dialect (RIF PRD)
The event and condition parts of the rule bodies in reactive rule dialects (RR)
Integrity constraints (IC)
It should be noted, however, that apart from RIF-BLD and RIF-PRD no decision has been made regarding which dialects will ultimately be part of RIF.
The condition sublanguage of RIF-BLD is intended to be used only in rule bodies and queries, not in rule heads. The various RIF dialects diverge in the way they specify, interpret, or use the formulas that occur in their heads and in other components of the rules. By focusing on the condition part of the rule bodies we achieve a great deal of syntactic and semantic reuse among the dialects.
This part of the document describes Positive Conditions and Slotted Conditions.