Results 1 - 10 of 186

Theory and Practice of Constraint Handling Rules

by Thom Frühwirth , 1998
"... Constraint Handling Rules (CHR) are our proposal to allow more flexibility and application-oriented customization of constraint systems. CHR are a declarative language extension especially designed for writing user-defined constraints. CHR are essentially a committed-choice language consisting of mu ..."
Abstract - Cited by 455 (37 self) - Add to MetaCart
Constraint Handling Rules (CHR) are our proposal to allow more flexibility and application-oriented customization of constraint systems. CHR are a declarative language extension especially designed for writing user-defined constraints. CHR are essentially a committed-choice language consisting

Extending CHR with negation as absence

by Peter Van Weert, Jon Sneyers, Tom Schrijvers, Bart Demoen, Peter Van Weert, Jon Sneyers, Tom Schrijvers, Bart Demoen - Dept. of Computer Science , 2006
"... In this exploratory paper, we introduce CHR ¬ , an extension of the CHR language with negation as absence, and we illustrate how the added expressiveness allows CHR programmers to write more declarative and concise rules. We show the difficulties of integrating negation with the conventional executi ..."
Abstract - Cited by 14 (10 self) - Add to MetaCart
In this exploratory paper, we introduce CHR ¬ , an extension of the CHR language with negation as absence, and we illustrate how the added expressiveness allows CHR programmers to write more declarative and concise rules. We show the difficulties of integrating negation with the conventional

Generalized CHR Machines

by Jon Sneyers, Thom Frühwirth
"... Constraint Handling Rules (CHR) is a high-level rule-based programming language. In [11], a model of computation based on the operational semantics of CHR is introduced, called the CHR machine. The CHR machine was used to prove a complexity-wise completeness result for the CHR language and its impl ..."
Abstract - Cited by 4 (4 self) - Add to MetaCart
Constraint Handling Rules (CHR) is a high-level rule-based programming language. In [11], a model of computation based on the operational semantics of CHR is introduced, called the CHR machine. The CHR machine was used to prove a complexity-wise completeness result for the CHR language and its

CHR for imperative host languages

by Peter Van Weert, Pieter Wuille, Tom Schrijvers, Bart Demoen - Issue of LNAI on Constraint Handling Rules , 2008
"... Abstract. In this paper, we address the different conceptual and technical difficulties encountered when embedding CHR into an imperative host language. We argue that a tight, natural integration leads to a powerful programming language extension, intuitive to both CHR and imperative programmers. We ..."
Abstract - Cited by 4 (3 self) - Add to MetaCart
Abstract. In this paper, we address the different conceptual and technical difficulties encountered when embedding CHR into an imperative host language. We argue that a tight, natural integration leads to a powerful programming language extension, intuitive to both CHR and imperative programmers

On the Expressive Power of Priorities in CHR

by Maurizio Gabbrielli , Jacopo Mauro , Maria Chiara Meo
"... Abstract Constraint Handling Rules (CHR) is a committed-choice declarative language which has been originally designed for writing constraint solvers and which is nowadays a general purpose language. Recently the language has been extended by introducing userdefinable (static or dynamic) rule prior ..."
Abstract - Add to MetaCart
Abstract Constraint Handling Rules (CHR) is a committed-choice declarative language which has been originally designed for writing constraint solvers and which is nowadays a general purpose language. Recently the language has been extended by introducing userdefinable (static or dynamic) rule

CHR for XSB

by Tom Schrijvers, David S. Warren, Bart Demoen - Proceedings of CICLOPS 2003. Technical Report DCC-2003-05, DCC - FC & LIACC, University of Porto , 2003
"... XSB is a highly declarative programming system consisting of Prolog extended with tabled resolution. It is useful for many tasks, some of which require constraint solving. Thus flexible and high level support for constraint systems is required. Constraint Handling Rules is exactly such a high level ..."
Abstract - Cited by 5 (4 self) - Add to MetaCart
language embedded in Prolog for writing application tailored constraint solvers. In this paper we present the integration of a CHR system in the XSB system and especially our findings on how to integrate CHR with tabled resolution, such as how to deal with issues as call abstraction of constraints

Aggregates in CHR

by Jon Sneyers, Peter Van Weert, Tom Schrijvers, Bart Demoen, Jon Sneyers, Peter Van Weert, Tom Schrijvers, Bart Demoen, Jon Sneyers, Peter Van Weert, Tom Schrijvers, Bart Demoen , 2007
"... We propose an extension of the Constraint Handling Rules language with aggregates like sum, count, findall, and min in the heads of rules. We define the semantics of aggregate expressions formally and informally. Our prototype implementation allows nested aggregate expressions over guarded conjuncti ..."
Abstract - Cited by 3 (3 self) - Add to MetaCart
We propose an extension of the Constraint Handling Rules language with aggregates like sum, count, findall, and min in the heads of rules. We define the semantics of aggregate expressions formally and informally. Our prototype implementation allows nested aggregate expressions over guarded

Parsing Natural Languages with CHR

by Frank Morawietz, Philippe Blache , 2002
"... In this paper, parsing as deduction and constraint programming are brought together to outline a procedure for the specification of constraint-based (chart) parsers. Extending the proposal in Shieber (1995) which provides a meta interpreter for several deduction systems, we show how to directly real ..."
Abstract - Add to MetaCart
realize the inference rules for chart parsers as Constraint Handling Rules (Frühwirth, 1998) by viewing the items of a conventional chart parser as constraints and the constraint base as a chart. This allows the direct use of the constraint resolution process to parse sentences in diverse natural language

CHR: A Flexible Query Language

by Slim Abdennadher, Heribert Schütz - IN FQAS ’98: PROCEEDINGS OF THE THIRD INTERNATIONAL CONFERENCE ON FLEXIBLE QUERY ANSWERING SYSTEMS
"... We show how the language CHR, a high-level logic language for the implementation of constraint solvers, can be slightly extended to become a general-purpose logic programming language with an expressive power subsuming the expressive power of Horn clause programs with SLD resolution. The extended la ..."
Abstract - Cited by 34 (2 self) - Add to MetaCart
We show how the language CHR, a high-level logic language for the implementation of constraint solvers, can be slightly extended to become a general-purpose logic programming language with an expressive power subsuming the expressive power of Horn clause programs with SLD resolution. The extended

On the expressive power of multiple heads in CHR

by Cinzia Di Giusto, Maurizio Gabbrielli , 804
"... Constraint Handling Rules (CHR) is a committed-choice declarative language which has been originally designed for writing constraint solvers and which is nowadays a general purpose language. CHR programs consist of multi-headed guarded rules which allow to rewrite constraints into simpler ones until ..."
Abstract - Add to MetaCart
Constraint Handling Rules (CHR) is a committed-choice declarative language which has been originally designed for writing constraint solvers and which is nowadays a general purpose language. CHR programs consist of multi-headed guarded rules which allow to rewrite constraints into simpler ones
Results 1 - 10 of 186