NDLI: Propagators and concurrent constraints

Content Provider	ACM Digital Library
Author	Laffra, Chris van den Bos, Jan
Abstract	A constraint is a numeric or geometric relationship between objects. Constraints have a declarative nature and are a natural way for describing relationships between objects. Combining constraint systems and object-oriented programming (OOP) appears hard. All existing systems implicitly compromise the encapsulation principle of OOP. Also, the constraint resolving mechanism is typically centralized, thereby restricting parallel execution of a constraint program. This paper proposes a mechanism that provides for constraints in the concurrent (parallel) object-oriented Procol environment. Constraints are implemented using propagators. Propagators are triggered by messages that are sent to objects. Propagator constraints are solved by local propagation of known state, intuitively allowing for parallel execution of a Procol constraint program.
Starting Page	68
Ending Page	72
Page Count	5
File Format	PDF
ISSN	10556400
DOI	10.1145/127070.127087
Journal	ACM SIGPLAN OOPS Messenger (OOPS)
Volume Number	2
Issue Number	2
Language	English
Publisher	Association for Computing Machinery (ACM)
Publisher Date	1991-07-01
Publisher Place	New York
Access Restriction	One Nation One Subscription (ONOS)
Content Type	Text
Resource Type	Article

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Propagators and concurrent constraints