CW 479

Leslie De Koninck, Tom Schrijvers, and Bart Demoen
CHR-rp: Constraint Handling Rules with rule priorties

Abstract

We extend the Constraint Handling Rules language (CHR) with user-defined rule priorities. This language extension reduces the level of non-determinism that is inherent to the theoretical operational semantics of CHR, and gives a more high-level form of execution control compared to the refined operational semantics. We suggest some application areas. A formal operational semantics for the extended language, called CHR-rp, is given and its theoretical properties are discussed. We look at some issues with CHR-rp and discuss alternatives for rule priorities.