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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2005

10.
Abdennadher, Slim; Frühwirth, Thom; Holzbaur, Christian
Editors, Special Issue on Constraint Handling Rules
Theory and Practice of Logic Programming, 5 (4-5)
2005
9.
Frühwirth, Thom
Specialization of Concurrent Guarded Multi-Set Transformation Rules
In Etalle, S., Editor, Logic-based Program Synthesis and Transformation (LOPSTR'04)Volume3573fromLecture Notes in Computer Science, Page 133-148
In Etalle, S., Editor
Publisher: Springer-Verlag
2005

2004

8.
Schrijvers, T.; Frühwirth, Thom
Implementing and Analysing Union-Find in CHR
Document Number: CW 389
Departement Computerwetenschappen, Katholieke Universiteit Leuven
July 2004
7.
Bistarelli, S.; Frühwirth, Thom; Marte, M.; Rossi, F.
Soft Constraint Propagation and Solving in Constraint Handling Rules
Computational Intelligence: Special Issue on Preferences in AI and CP, 20 (2) :287-307
May 2004
6.
Abdennadher, Slim; Frühwirth, Thom
Integration and Optimization of Rule-based Constraint Solvers
In Bruynooghe, M., Editor, Logic-based Program Synthesis and Transformation (LOPSTR'03)Volume3018fromLecture Notes in Computer Science, Page 198-213
In Bruynooghe, M., Editor
Publisher: Springer-Verlag
2004

2003

5.
Frühwirth, Thom; Abdennadher, Slim
Essentials of Constraint Programming
Publisher: Springer-Verlag
February 2003
4.
Abdennadher, Slim; Frühwirth, Thom
Integration and Optimization of Rule-based Constraint Solvers
International Symposium on Logic-based Program Synthesis and Transformation (LOPSTR'03)
2003
3.
Frühwirth, Thom; Holzbaur, Christian
Source-to-Source Transformation for a Class of Expressive Rules
In Buccafurri, F., Editor, Joint Conference on Declarative Programming APPIA-GULP-PRODE 2003 (AGP 2003), Page 386-397
In Buccafurri, F., Editor
2003

2002

2.
Frühwirth, Thom
As Time Goes By II: More Automatic Complexity Analysis of Concurrent Rule Programs
In Di Pierro, A. and Wiklicky, H., Editor, Quantitative Aspects of Programming Laguages, QAPL'01Volume59fromElectronic Notes in Theoretical Computer Science, Page 185-206
In Di Pierro, A. and Wiklicky, H., Editor
November 2002
1.
Frühwirth, Thom; Di Pierro, A.; Wiklicky, H.
Probabilistic Constraint Handling Rules
In Comini, M. and Falaschi, M., Editor, 11th International Workshop on Functional and (Constraint) Logic Programming, WFLP 2002Volume76fromElectronic Notes in Theoretical Computer Science, Page 115-130
In Comini, M. and Falaschi, M., Editor
November 2002