Declarative laziness in a concurrent constraint language
Aod Fred Spiessens, Raphaël Collet, Peter Van Roy · 2003
This paper explains how to design and implement an extension for by-need synchronization for a confluent (subset of a) multiparadigm concurrent constraint language, while keeping the extended language confluent. It reveals the subtleties and pitfalls that can easily lead to the loss of confluence, especially in languages with a powerful unification operator. The authors report on their own experiences, and provide guidelines for similar projects, based on considerations regarding the monotonicity of the constraint store. This paper also explores the boundaries of confluent extensibility for such languages.