Institute of Software Engineering and Programming Languages

CHR Research Group

Constraint Handling Rules (CHR) is a concurrent committed-choice constraint logic programming language consisting of guarded rules that transform multi-sets of atomic formulas (constraints) until exhaustion. It was designed by Thom Fruehwirth in 1991. CHR can embed many rule-based formalisms and systems, and it can describe algorithms in a compact declarative way without compromising efficiency. The clean semantics of CHR ensures that several desirable properties hold for CHR programs and also facilitates sophisticated program analysis. CHR libraries exist for Prolog, Haskell, Java, Javascript, Python and C. CHR is also available online for experimentation with many example programs. More than 250 academic and industrial projects worldwide use CHR, and about 2500 research papers reference it.

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2007

25.
Djelloul, Khalil; Dao, T.-B.-H.; Frühwirth, Thom
Toward a first-order extension of Prolog's unification using CHR: a CHR first-order constraint solver over finite or infinite trees
In Hung, C. C. and Rosa, A., Editor, Proceedings of the 2007 ACM symposium on Applied computing, SAC 2007, Seite 58-64
In Hung, C. C. and Rosa, A., Editor
Herausgeber: ACM Press
2007
DOI:10.1145/1244002.1244016

2006

24.
Frühwirth, Thom
Deriving Linear-Time Algorithms from Union-Find in CHR
In Schrijvers, T. and Frühwirth, T., Editor, Proceedings of CHR 2006, Third Workshop on Constraint Handling RulesausTechnical Report, Seite 49-60
In Schrijvers, T. and Frühwirth, T., Editor
Herausgeber: Departement Computerwetenschappen, Katholieke Universiteit Leuven
Juni 2006
23.
Meister, Marc; Frühwirth, Thom
Complexity of the CHR Rational Tree Equation Solver
In Schrijvers, T. and Frühwirth, T., Editor, Proceedings of CHR 2006, Third Workshop on Constraint Handling RulesausTechnical Report, Seite 77-92
In Schrijvers, T. and Frühwirth, T., Editor
Herausgeber: Departement Computerwetenschappen, Katholieke Universiteit Leuven
Juni 2006
22.
Schrijvers, T.; Frühwirth, Thom
Programming Pearl: Optimal Union-Find in Constraint Handling Rules
Theory and Practice of Logic Programming, 6 (1-2) :213-224
Januar 2006
21.
Frühwirth, Thom; Abdennadher, Slim
Principles of constraint systems and constraint solvers
Archives of Control Sciences: Special Issue on Constraint Programming, 16 (2)
2006
20.
Schrijvers, T.; Demoen, B.; Duck, G.; Stuckey, P.; Frühwirth, Thom
Automatic implication checking for CHR constraints
In Cirstea, H. and Martí-Oliet, N., Editor, Proceedings of the 6th International Workshop on Rule-Based Programming, RULE 2005Band147ausElectronic Notes in Theoretical Computer Science, Seite 93-111
In Cirstea, H. and Martí-Oliet, N., Editor
Januar 2006
19.
Frühwirth, Thom; Michel, L.; Schulte, C.
Constraints in Procedural and Concurrent Languages
In Rossi, F. and Beek, P. van and Walsh, T., Editor, Handbook of Constraint Programming
Kapitel 13
Herausgeber: Elsevier
2006
18.
Frühwirth, Thom
Constraint Handling Rules: The Story So Far
In Maher, M., Editor, Proceedings of the Eigth ACM SIGPLAN Symposium on Principles and Practice of Declarative Programming, Seite 13-14
In Maher, M., Editor
Herausgeber: ACM Press
2006
DOI:10.1145/1140335.1140337
17.
Frühwirth, Thom
Complete Propagation Rules for Lexicographic Order Constraints over Arbitrary Domains
In Hnich, B. and Carlsson, M. and Fages, F. and Rossi, F., Editor, Recent Advances in Constraints, CSCLP 2005Band3978ausLecture Notes in Computer Science, Seite 14-28
In Hnich, B. and Carlsson, M. and Fages, F. and Rossi, F., Editor
Herausgeber: Springer-Verlag
2006
DOI:10.1007/11754602_2

2005

16.
Frühwirth, Thom
Parallelizing Union-Find in Constraint Handling Rules Using Confluence
In Gabbrielli, M. and Gupta G., Editor, Logic Programming: 21st International Conference, ICLP 2005Band3668ausLecture Notes in Computer Science, Seite 113-127
In Gabbrielli, M. and Gupta G., Editor
Herausgeber: Springer-Verlag
Oktober 2005