DFKI Research Report-94-16



Language: English

by Gert Smolka

A Foundation for Higher-order Concurrent Constraint Programming

26 Pages


We present the gamma-calculus, a computational calculus for higher-order concurrent programming. The calculus can elegantly express higher-order functions (both eager and lazy) and concurrent objects with encapsulated state and multiple inheritance. The primitives of the gamma-calculus are logic variables, names, procedural abstraction, and cells. Cells provide a notion of state that is fully compatible with concurrency and constraints. Although it does not have a dedicated communication primitive, the gamma-calculus can elegantly express one-to-many and many-to-one communication.

There is an interesting relationship between the gamma-calculus and the pi-calculus: The gamma-calculus is subsumed by a calculus obtained by extending the asynchronous and polyadic pi-calculus with logic variables.

The gamma-calculus can be extended with primitives providing for constraint-based problem solving in the style of logic programming. A such extended gamma-calculus has the remarkable property that it combines first-order constraints with higher-order programming.

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DFKI-Bibliothek (bib@dfki.uni-kl.de)

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