A declarative coordination language

Abstract

We describe Gammalog, a logic language whose semantics is based on the chemical metaphor. The language combines the ability of describing coordination by transformation rules on a shared-dataspace, as in Gamma, with the execution model of logic programming. The main feature of Gammalog is that the declarative reading of programs is not restricted to the pure logic language but it also includes the coordination mechanisms. This feature makes Gammalog a promising alternative to other coordination models which can be embedded in logic programming. We present the language syntax, its formal semantics, and a prototype implementation based on Gödel, which inherits its strongly typed framework. As an example of the expressive power of the language we provide the specification of a simple operating system.