Join-calculus


The join-calculus is a process calculus developed at INRIA. The join-calculus was developed to provide a formal basis for the design of distributed programming languages, and therefore intentionally avoids communication constructs found in other process calculi, such as rendezvous communications, which are difficult to implement in a distributed setting. Despite this limitation, the join-calculus is as expressive as the full π-calculus. Encodings of the π-calculus in the join-calculus, and vice versa, have been demonstrated.
The join-calculus is a member of the π-calculus family of process calculi, and can be considered, at its core, an asynchronous π-calculus with several strong restrictions:
  • Scope restriction, reception, and replicated reception are syntactically merged into a single construct, the definition;
  • Communication occurs only on defined names;
  • For every defined name there is exactly one replicated reception.
However, as a language for programming, the join-calculus offers at least one convenience over the π-calculus — namely the use of multi-way join patterns, the ability to match against messages from multiple channels simultaneously.

Implementations

Languages based on the join-calculus

The join-calculus programming language is a new language based on the join-calculus process calculus. It is implemented as an interpreter written in OCaml, and supports statically typed distributed programming, transparent remote communication, agent-based mobility, and some failure-detection.
  • Though not explicitly based on join-calculus, the rule system of CLIPS implements it if every rule deletes its inputs when triggered.
Many implementations of the join-calculus were made as extensions of existing programming languages:

Embeddings in other programming languages

These implementations do not change the underlying programming language but introduce join calculus operations through a custom library or DSL: