Abstract

General term graph rewriting is a powerful computational model, suitable for implementing a wide variety of declarative language paradigms. Here, we address the problems involved in the implementation, on a loosely-coupled architecture, of an intermediate language based on term graph rewriting, DACTL. In general, such problems are severe, so a subset of this language called MONSTR is defined, free from some of the inefficiencies in the original model (such as an excessive necessity for locking). Superficially, much of the expressiveness of the original model is compromised thereby, especially with regard to the implementation of concurrent logic languages. However, transformation techniques that are valid in the context of declarative language translations, and that map fairly general DACTL rule sets to equivalent MONSTR rule sets without endangering the semantics of the former can be defined. These techniques use shared graph nodes that reflect states of computation, and are similar to the logical variable.

Citations