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.

Klick here for more information on our research.

2010

40.
Betz, Hariolf; Raiser, Frank; Frühwirth, Thom
Persistent Constraints in Constraint Handling Rules
In Geske, U. and Wolf, A., Editor, Proceedings of the 23rd Workshop on (Constraint) Logic Programming 2009, Page 155-166
In Geske, U. and Wolf, A., Editor
Publisher: Universitätsverlag Potsdam
March 2010
39.
Betz, Hariolf; Raiser, Frank; Frühwirth, Thom
A Complete and Terminating Execution Model for Constraint Handling Rules
from Ulmer Informatik-Berichte
Document Number: 2010-01
Universität Ulm
January 2010

2009

38.
Raiser, Frank; Frühwirth, Thom
Strong Joinability Analysis for Graph Transformation Systems in CHR
In Corradini, A., Editor, Proceedings of the Fifth International Workshop on Computing with Terms and Graphs (TERMGRAPH 2009)Volume253fromElectronic Notes in Theoretical Computer Science, Page 91-111
In Corradini, A., Editor
November 2009
DOI:10.1016/j.entcs.2009.10.019
37.
Raiser, Frank; Betz, Hariolf; Frühwirth, Thom
Equivalence of CHR States Revisited
In Raiser, F. and Sneyers, J., Editor, CHR 2009: Proceedings of the Sixth International Workshop on Constraint Handling RulesfromTechnical Report, Page 34-48
In Raiser, F. and Sneyers, J., Editor
Publisher: Departement Computerwetenschappen, Katholieke Universiteit Leuven
July 2009
36.
Raiser, Frank; Frühwirth, Thom
Operational Equivalence of Graph Transformation Systems
In Raiser, F. and Sneyers, J., Editor, CHR 2009: Proceedings of the Sixth International Workshop on Constraint Handling RulesfromTechnical Report, Page 49-61
In Raiser, F. and Sneyers, J., Editor
Publisher: Departement Computerwetenschappen, Katholieke Universiteit Leuven
July 2009
35.
Frühwirth, Thom
Constraint Handling Rules
Publisher: Cambridge University Press
2009
34.
Raiser, Frank; Frühwirth, Thom
Strong joinability analysis for graph transformation systems in CHR
In Corradini, A., Editor, Preliminary Proceedings of the 5th International Workshop on Computing with Terms and Graphs (TERMGRAPH), Page 97-112
In Corradini, A., Editor
2009
DOI:10.1016/j.entcs.2009.10.019

2008

33.
Raiser, Frank; Frühwirth, Thom
Towards Term Rewriting Systems in Constraint Handling Rules
In Schrijvers, T. and Raiser, F. and Frühwirth, T., Editor, CHR 2008, The 5th Workshop on Constraint Handling Rules, Page 19-33
In Schrijvers, T. and Raiser, F. and Frühwirth, T., Editor
July 2008
32.
Sneyers, Jon; Frühwirth, Thom
Generalized CHR Machines
In Schrijvers, T. and Raiser, F. and Frühwirth, T., Editor, CHR 2008, The 5th Workshop on Constraint Handling Rules, Page 143-157
In Schrijvers, T. and Raiser, F. and Frühwirth, T., Editor
July 2008
31.
Djelloul, Khalil; Dao, T.-B.-H.; Frühwirth, Thom
Theory of finite or infinite trees revisited
Theory and Practice of Logic Programming, 8 (4) :431-489
July 2008
DOI:10.1017/S1471068407003171