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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2020

95.
Frühwirth, Thom
Repeated Recursion Unfolding for Super-Linear Speedup within Bounds
Pre-Proceedings of the 30th International Symposium on Logic-Based Program Synthesis and Transformation (LOPSTR 2020)
September 2020
File:https://arxiv.org/abs/2009.05314

2019

94.
Frühwirth, Thom
Justifications in Constraint Handling Rules for Logical Retraction in Dynamic Algorithms: Theory, Implementations, and Complexity
Journal Fundamenta Informaticae
2019
Publisher: IOS Press

2018

93.
Frühwirth, Thom
The Computer Art of Mason's Mark Design with VanDeGraphGenerator
Publisher: BOD
October 2018
ISBN:9783752842975
File:https://books.google.de/books?id=w3hoDwAAQBAJ
92.
Gall, Daniel; Frühwirth, Thom
An Operational Semantics for the Cognitive Architecture ACT-R and its Translation to Constraint Handling Rules
ACM Transactions on Computational Logic (TOCL), 19 (3)
September 2018
DOI:10.1145/3218818
File:https://arxiv.org/abs/1702.01606
91.
Frühwirth, Thom; Gall, Daniel
Exploring Parallel Execution Strategies for Constraint Handling Rules
26th International Workshop on Functional and Logic Programming, Frankfurt am Main, Germany
September 2018
File:https://arxiv.org/abs/1808.07788
90.
Frühwirth, Thom
Rule-Based Drawing, Analysis and Generation of Graphs for Mason's Mark Designs
Proceedings of the 2nd International Joint Conference on Rules and Reasoning (RuleML+RR 2018)
2nd International Joint Conference on Rules and Reasoning (RuleML+RR 2018)
Luxembourg
September 2018
September 2018
File:pdfhttp://www.informatik.uni-ulm.de/pm/mitarbeiter/fruehwirth/drafts/masonmarks-final0.pdf
89.
Frühwirth, Thom
Implementation of Logical Retraction in Constraint Handling Rules with Justifications (full version)
In Dietmar Seipel, Michael Hanus, Salvador Abreu, Editor, Declarative Programming and Knowledge Management, Proceedings of the Conference on Declarative Programming DECLARE 2017, Revised Selected PapersVolume10997, Page 37--52
DECLARE 2017
Würzburg
17.-22.09.2017
In Dietmar Seipel, Michael Hanus, Salvador Abreu, Editor
Publisher: Springer
September 2018
DOI:10.1007/978-3-030-00801-7_3
File:pdfhttp://www.informatik.uni-ulm.de/pm/mitarbeiter/fruehwirth/drafts/chr-just-impl-final-full.pdf
88.
Nogatz, Falco; Frühwirth, Thom; Seipel, Dietmar
CHR.js: A CHR Implementation in JavaScript
Proceedings of the 2nd International Joint Conference on Rules and Reasoning (RuleML+RR 2018), Luxembourg, September 2018
2nd International Joint Conference on Rules and Reasoning (RuleML+RR 2018)
Luxembourg
September 2018
September 2018
File:pdfhttp://www.informatik.uni-ulm.de/pm/mitarbeiter/fruehwirth/drafts/Nogatz-draft.pdf
87.
Sharaf, Nada; Abdennadher, Slim; Frühwirth, Thom
CHRvis: Syntax and Semantics
Technical Communications of the 34th International Conference on Logic Programming (ICLP 2018)
34th International Conference on Logic Programming (ICLP 2018)
Oxford, UK
July 2018
July 2018
86.
Frühwirth, Thom
A Rule-Based Tool for Analysis and Generation of Graphs Applied to Mason's Marks
Proceedings of the Workshop on Logic and Practice of Programming (LPoP 2018)
Workshop on Logic and Practice of Programming (LPoP 2018)
Oxford, UK
2018-07-18
July 2018
File:pdfhttps://www.uni-ulm.de/fileadmin/website_uni_ulm/iui.inst.170/home/gall/publications/fru_masonmarks-short-final.pdf