Approved PRD Modify Action of RIF PRD Demonstrates the modify action in RIF PRD. The rule decrements a frame slot until it reaches 0. Modify_loop-premise.rif http://www.w3.org/2005/rules/test/repository/tc/Modify_loop/Modify_loop-premise.rif ) Prefix(func ) Prefix(pred ) Group ( Forall ?X ?C ( If And( ?X[ex:count -> ?C] pred:numeric-greater-than(?C 0) ) Then Do ( Modify (?X[ex:count-> func:numeric-subtract(?C 1)]) ) ) ex:foo[ex:count -> 10] ) ) ]]> Modify_loop-conclusion.rif http://www.w3.org/2005/rules/test/repository/tc/Modify_loop/Modify_loop-conclusion.rif 0] ]]>