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.

2015

70.
Gall, Daniel; Frühwirth, Thom
A Formal Semantics for the Cognitive Architecture ACT-R
, Revised Selected Papers of the 24th International Symposium on Logic-Based Program Synthesis and Transformation (LOPSTR 2014)Volume8981
Publisher: Springer LNCS
September 2015
DOI:10.1007/978-3-319-17822-6_5
File:pdfhttp://www.informatik.uni-ulm.de/pm/mitarbeiter/fruehwirth/drafts/act-r-semantics-2015.pdf
69.
Sharaf, Nada; Abdennadher, Slim; Frühwirth, Thom
CHRAnimation: An Animation Tool for Constraint Handling Rules
, Revised Selected Papers of the 24th International Symposium on Logic-Based Program Synthesis and Transformation (LOPSTR 2014)Volume8981
Publisher: Springer LNCS
September 2015
File:pdfhttp://www.informatik.uni-ulm.de/pm/mitarbeiter/fruehwirth/drafts/chr-animation-2015.pdf
68.
Zaki, Amira; Abdennadher, Slim; Frühwirth, Thom
Combining Forward and Backward Propagation
10th International Symposium on Frontiers of Combining Systems (FroCoS'15)
September 2015
DOI:10.1007/978-3-319-24246-0_19
File:pdfhttp://www.informatik.uni-ulm.de/pm/mitarbeiter/fruehwirth/drafts/zaki-frocos-2015.pdf
67.
Frühwirth, Thom
Constraint Handling Rules - What Else?
Invited Survey Paper, The 9th International Web Rule Symposium (RuleML)
August 2015
DOI:10.1007/978-3-319-21542-6_2
File:pdfhttp://www.informatik.uni-ulm.de/pm/mitarbeiter/fruehwirth/drafts/ruleML-keynote-chr-survey-15.pdf
66.
Frühwirth, Thom
A Devil's Advocate against Termination of Direct Recursion
ACM 17th International Symposium on Principles and Practice of Declarative Programming (PPDP 2015), Siena, Italy
July 2015
File:pdfhttp://www.informatik.uni-ulm.de/pm/mitarbeiter/fruehwirth/drafts/devils-advocate-ppdp-15.pdf
65.
Gall, Daniel; Frühwirth, Thom
A Refined Operational Semantics for ACT-R
ACM 17th International Symposium on Principles and Practice of Declarative Programming (PPDP 2015), Siena, Italy
July 2015
DOI:10.1145/2790449.2790517
64.
Sharaf, Nada; Abdennadher, Slim; Frühwirth, Thom
DiagrammaticCHR: A Diagrammatic Representation of CHR Program
19th International Conference Information Visualisation (iV2015)
Publisher: IEEE Digital Library
July 2015
DOI:10.1109/iV.2015.31
63.
Dahl, Veronica; Tessaris, Sergio; Frühwirth, Thom
Imperfect Querying through Womb Grammars plus Ontologies
Workshop Ontologies and Logic Programming for Query Answering (ONTOLP'15) at IJCAI-2015, Buenos Aires
July 2015
DOI:10.1109/iV.2015.31
62.
Gall, Daniel; Frühwirth, Thom
An Adaptable Implementation of ACT-R with Refraction in Constraint Handling Rules
13th International Conference on Cognitive Modeling (ICCM), Groningen
April 2015

2014

61.
Sharaf, Nada; Abdennadher, Slim; Frühwirth, Thom
A Visualization Tool for Constraint Handling Rules
24th International Symposium on Logic-Based Program Synthesis and Transformation (LOPSTR 2014), Canterbury, UK
September 2014