Non-deterministic computations greatly enhance the expressive power of functional logic programs, but are often computationally expensive. We analyze a programming technique that improves the time and memory efficiency of some non-deterministic computations. This technique relies on the introduction of a new symbol into the signature of a program. This symbol may be treated either as a polymorphic defined operation or as an overloaded constructor. Our programming technique may save execution time, by reducing the number of steps of a computation. The technique may also save memory, by reducing the number of terms constructed by a computation. We give some examples of the application of our technique, address its soundness and completeness, and informally reason about its impact on the efficiency of computations.
Supported in part by NSF grants INT-9981317 and CCR-0110496 and by the Spanish Knowledge Society Foundation, the Spanish Research Funding Agency (CICYT) TIC 2001-2705-C03-01, by Acción Integrade Hispano-Italiana HI2000-0161, and the Valencian Research Council under grant GV01-424.
