Recent functional logic languages such as Curry and Toy combine lazy functional programming with logic programming features including logic variables, non-determinism, unification, narrowing, fair search, concurrency, and residuation. In this paper, we show how to extend a conventional interpreter for a lazy functional language to handle these features by adding support for reference cells, process-like and thread-like concurrency mechanisms, and a novel form of multi-versioned store. Our interpretation scheme is practical, and can be easily extended to perform compilation. The language specified by our interpreter is designed so that programs are deterministic in a novel and useful sense. Categories and Subject Descriptors: D.3.2. [Programming Languages]: Language Classifications--Multiparadigm languages, Applicative (functional) languages, Constraint and logic languages; D.3.4. [Programming Languages]: Language Processors--Interpreters, Run-time environments General Terms: Languages...
Andrew P. Tolmach, Sergio Antoy, Marius Nita