Constraint Handling Rules (CHR) is both an effective concurrent declarative constraint-based programming language and a versatile computational formalism. While conceptually simple, CHR is distinguished by a remarkable combination of desirable features:
a semantic foundation in classical and linear logic,
an effective and efficient sequential and parallel execution model
guaranteed properties like the anytime online algorithm properties
powerful analysis methods for deciding essential program properties.
This overview of some CHR-related research and applications is by no means meant to be complete. Essential introductory reading for CHR provide the survey article [
] and the books [
]. Up-to-date information on CHR can be found online at the CHR web-page
, including the slides of the keynote talk associated with this article. In addition, the CHR website
offers everything you want to know about CHR, including online demo versions and free downloads of the language.