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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2006

20.
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, Page 13-14
In Maher, M., Editor
Publisher: ACM Press
2006
DOI:10.1145/1140335.1140337
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
Chapter 13
Publisher: Elsevier
2006
18.
Frühwirth, Thom; Abdennadher, Slim
Principles of constraint systems and constraint solvers
Archives of Control Sciences: Special Issue on Constraint Programming, 16 (2)
2006
17.
Schrijvers, T.; Frühwirth, Thom
Programming Pearl: Optimal Union-Find in Constraint Handling Rules
Theory and Practice of Logic Programming, 6 (1-2) :213-224
January 2006

2005

16.
Betz, Hariolf; Frühwirth, Thom
A Linear-Logic Semantics for Constraint Handling Rules
In van Beek, P., Editor, 11th Conference on Principles and Practice of Constraint Programming CP 2005Volume3709fromLecture Notes in Computer Science, Page 137-151
In van Beek, P., Editor
Publisher: Springer-Verlag
October 2005
DOI:10.1007/11564751_13
15.
Frühwirth, Thom
Parallelizing Union-Find in Constraint Handling Rules Using Confluence
In Gabbrielli, M. and Gupta G., Editor, Logic Programming: 21st International Conference, ICLP 2005Volume3668fromLecture Notes in Computer Science, Page 113-127
In Gabbrielli, M. and Gupta G., Editor
Publisher: Springer-Verlag
October 2005
14.
Frühwirth, Thom
Logical Rules for a Lexicographic Order Constraint Solver
In Schrijvers, T. and Frühwirth, T., Editor, Proceedings of CHR 2005, Second Workshop on Constraint Handling RulesfromTechnical Report, Page 79-91
Departement Computerwetenschappen, Katholieke Universiteit Leuven
In Schrijvers, T. and Frühwirth, T., Editor
September 2005
13.
Schrijvers, T.; Demoen, B.; Duck, G.; Stuckey, P.; Frühwirth, Thom
Automatic implication checking for CHR constraints
6th International Workshop on Rule-Based Programming
April 2005
12.
Schrijvers, T.; Frühwirth, Thom
Analysing the CHR Implementation of Union-Find
In Wolf, A. and Frühwirth, T. and Meister, M., Editor, 19th Workshop on (Constraint) Logic Programming W(C)LP 2005fromUlmer Informatik-Berichte, Page 135-146
Universität Ulm
In Wolf, A. and Frühwirth, T. and Meister, M., Editor
February 2005
11.
Schrijvers, T.; Demoen, B.; Duck, G. J.; Stuckey, P. J.; Frühwirth, Thom
Automatic implication checking for CHR constraint solvers
Document Number: CW 402
Departement Computerwetenschappen, Katholieke Universiteit Leuven
January 2005