CHR 2014 Workshop

On July 18th 2014, the 11th International Workshop on CHR will take place in Vienna, Austria. The workshop is affiliated with ICLP and RTA, as a part of FLoC 2014 and the Vienna Summer of Logic.

More information

SecuritEase talk

The slides of Mike Elston's ICLP 2012 invited talk are now available on this website. The talk was titled Prolog and CHR in Finance: An easier way to occupy Wall Street?

Also, the invididual CHR'12 papers are now available at the on-line CHR bibliography, as well as the full proceedings.

CHR Cheatsheet

Amira Zaki et al made a CHR Cheatsheet, a document containing many hints for advanced programming in CHR. You can download it here.

CHR papers in TPLP

Two CHR-related papers made it in the top-10 of most downloaded papers of Theory and Practice of Logic Programming:

The latter is also one of the most cited articles of TPLP.

Summer school and workshop in Cairo

The Second CHR Summer school and the Eighth CHR workshop in Cairo in September 2011 were a big success. We reached the limit of 50 participants for the workshop and had lively discussions at both events.

The lecture slides and the workshop proceedings are now online for download. The workshop proceedings and individual papers are also available on this website at the CHR bibliography (look for the keyword CHR 2011).

New book on CHR

A new book on CHR has been published. The book presents recent research in implementation, extensions, and novel analyses of CHR.

It starts with a concise and research-oriented introduction to CHR. After that, carefully selected chapters from recent PhD theses provide detailed information on the topics of compilation and optimization, execution strategies, and formal analysis of CHR. These chapters can be read individually based on the reader's interest.

The chapters have been edited by Thom Frühwirth and Frank Raiser to better suit the book's general theme. Additionally, the book has been reviewed by the individual authors of the chapters, the editors, and Florian Geiselhart and Johannes Langbein. The involved PhD theses are the following: Gregory J. Duck (2005), Leslie De Koninck (2008), Edmund S. L. Lam (2010), Frank Raiser (2010), Tom Schrijvers (2005), and Jon Sneyers (2008).

Thom Frühwirth, Frank Raiser (editors). Constraint Handling Rules: Compilation, Execution, and Analysis. Textbook, ISBN 978-3-83-911591-6, March 2011.

Assistant Position at University of Ulm

A research/teaching position is available for Ph.D. students or postdocs at the Faculty of Computer Science, University of Ulm, Department of Software Engineering and Compiler Construction in the area of Constraint Programming, in particular Constraint Handling Rules (CHR).

At least a master or equivalent in computer science or strongly related area is required. The initial appointment will be for two years, beginning as soon as possible, with a possible renewal for another two years.

Read the announcement for more information.

CHR summer school

The First CHR Summer School took place last week in Leuven, Belgium. There were 41 participants and 7 lecturers. At the second day of the summer school, a CHR programming contest was organized. The results (and questions) of this First CHR Programming Contest are available here.

New CHR website!

As you've probably noticed by now, the CHR website has been redesigned. The old website is still available on this location in case you cannot get used to the new layout. Your comments are welcome.

News Archive

  • Jon Sneyers and Peter Van Weert are taking over as official maintainers of the CHR website.
  • This summer the First International Summer School on Constraint Handling Rules will be held in Leuven. During the week from August 30 till September 3, five internationally renowned researchers will give courses covering a wide range of theoretical and practical CHR related topics. The summer school will provide a lively, friendly forum where participants can get familiar with our state-of-the-art declarative rule-based programming tools, and gain insights into the analysis of these programs. No prior knowledge is assumed, so anyone interested is invited to register!
  • Johannes Langbein has developed a SWI-Prolog-based checker for state equivalence of CHR states and confluence of terminating CHR programs.
  • Andrei Melnikov has patched Michael Stahl's STM-based CHR implementation for Haskell to work with GHC 6.10.4.
  • Thierry Martinez has made his CHRat, modular CHR with ask and tell, available online.
  • The CHR 2010 Workshop will be held July 20, 2010 in Edinburgh (Scotland) at the occasion of ICLP 2010 (part of FLoC 2010).
  • Constraint Handling Rules, Thom Fruehwirth, Cambridge University Press, ISBN 9780521877763, July 2009.

Older news


11th CHR Workshop

Vienna Summer of Logic On July 18th 2014, the CHR 2014 Workshop will take place in Vienna, Austria. The workshop is affiliated with ICLP and RTA, as a part of FLoC 2014 and the Vienna Summer of Logic.

more information

10th CHR Workshop

Berlin The CHR 2013 Workshop will be organized on July 13th, 2013 in Berlin (Germany), collocated with the third CHR summer school.

more information

3rd CHR Summer School

Berlin “Third time's the charm” - After the success of the first and second CHR summer schools, a third one will take place in Berlin, Germany, from 8th till the 12th of July, 2013.

more information

9th CHR Workshop

Budapest The CHR 2012 Workshop will be organized on September 4th, 2012 in Budapest (Hungary), collocated with ICLP 2012.

more information

CHR Survey

The survey of CHR research from 1998 to 2007 is one of the most downloaded papers in TPLP. The on-line CHR bibliography was originally based on this survey.

CHR survey / CHR bibliography

8th CHR Workshop

GUC The CHR 2011 Workshop was held September 8th, 2011 in Cairo (Egypt) at the end of the second CHR summer school.

more information

2nd CHR Summer School

Cairo After its success last year in Belgium and to celebrate the 20th birthday of CHR, the Second CHR Summer School took place this year in Cairo, Egypt.

more information

CHR Summer School

Leuven The first international summer school on Constraint Handling Rules was organized from August 30 until September 3, 2010 in Leuven, Belgium.

more information

7th CHR Workshop

Edinburgh The CHR 2010 Workshop was held July 20, 2010 in Edinburgh (Scotland) at the occasion of ICLP 2010 (part of FLoC 2010), the premier international venue for presenting research in logic programming.

more information

CHR Book

CHR book cover Thom Frühwirth. Constraint Handling Rules. Cambridge University Press, 2009.

The standard reference authored by the designer of CHR - Provides a CHR tutorial for easy introduction - An essential source for researchers, lecturers, graduate students and professional programmers.

more information

CHR Mailing List

Subscribe to the CHR mailing list to get announcements of CHR-related events and to discuss about CHR.