A state equivalence and confluence checker for CHR

Johannes Langbein, Frank Raiser, and Thom Frühwirth. A state equivalence and confluence checker for CHR. 2010, CHR '10: Proc. 7th Workshop on Constraint Handling Rules, Workshop


Analyzing confluence of CHR programs manually can be an impractical and time consuming task. Based on a new theorem for state equivalence, this work presents the first tool for testing equivalence of CHR states. As state equivalence is an essential component of confluence analysis, we apply this tool in the development of a confluence checker that overcomes limitations of existing checkers. We further provide evaluation results for both tools and detail their modular design, which allows for extensions and reuse in future implementations of CHR tools.