Permit restricted form of equality
A (say, Horn) logic with restricted equality can be used to define functions via (left-to-right-)oriented equations, corresponding to rewrite rules. Function calls can be nested, thus avoiding the shared logic variables necessary in equivalent relational conjunctions. Restricted equality facilitates RIF interoperation and interchange with algebraic specifications as well as with functional Web languages such as MathML, XSLT, and XQuery. Such first-order functions also open an extension path to higher-order formalisms as well as to functional built-ins and functions & operators in production rule systems.
Position in the DC structure
Level: [Requirement] [PROPOSED]
list (by names) other DCs that depend on that one or on which it depends
DCs which depend on this
Alignment, Extension, Language coherency
Where does this design constraint come from? E.g. the charter, one or more of the already published UC, one or more of the rule systems listed in RIFRAF, an UC not covered in the current version of UCR
Parameterized function calls are often used to introduce new data instances as well as new operations and as such provide an important extension mechanism. For example, new logical operations are introduced in MathML by such a mechanism.
This requirement in effect is asking for the ability to extend RIF by packaging a collection of rules for action on specific data. It seems sensible to require this ability extend by combining pieces.
RIF without that is of limited use for me / RIF would be better with that.