1994
The paper presents an extension of the concurrent constraint model providing for higher-order programming, deep guards, and encapsulated search. The paper focuses on a higher-order combinator providing for encapsulated search. The search combinator spawns a local computation space and resolves remaining choices by returning the alternatives as first-class citizens. The search combinator allows to program different search strategies, including depth-first, indeterministic one solution, demand-driven multiple solution, all solutions, and best solution (branch and bound) search. The described computation model is realized in Oz, a programming language and system under development at DFKI.
Logic Programming: Proceedings of the 1994 International Symposium, Nov 1994, MIT-Press