Encapsulated Search for Higher-order Concurrent Constraint Programming

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 rst-class citizens. The search combinator allows to program diierent search strategies, including depth-rst, 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.