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.[1] 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.[1]
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:[1]
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.[2]
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.[3]
Though not explicitly based on join-calculus, the rule system of CLIPS implements it if every rule deletes its inputs when triggered (retracts the relevant facts when fired).
Many implementations of the join-calculus were made as extensions of existing programming languages:
JoCaml is a version of OCaml extended with join-calculus primitives
