This paper introduces a framework for the specification of tree search strategies in CHR with disjunction (CHR-or). We support the specification of common search strategies such as depth-first, breadth-first and best-first, as well as
constrained optimization by means of branch & bound search.
The framework is given as an extension of CHR with rule priorities (CHR-rp) in which each branch of the search tree is assigned a branch priority. This approach leads to a uniform solution to execution control in CHR.
In special issue of Lecture Notes in Artificial Intelligence on Constraint Handling Rules: Current Research Topics; editors: Tom Schrijvers and Thom Frühwirth