User-definable rule priorities for CHR
Leslie De Koninck, Tom Schrijvers, Bart Demoen · 2007
This paper introduces CHRrp: Constraint Handling Rules with user-definable rule priorities. CHRrp offers flexible execution control which is lacking in CHR. A formal operational semantics for the extended language is given and is shown to be an instance of the theoretical operational semantics of CHR. It is discussed how the CHR rp semantics influences confluence results. A translation scheme for CHRrp programs with static rule priorities into (regular) CHR is presented. The translation is proven correct and bench-mark results are given. CHRrp is related to priority systems in other constraint programming and rule based languages.