The join-calculus is a
process calculus
In computer science, the process calculi (or process algebras) are a diverse family of related approaches for formally modelling concurrent systems. Process calculi provide a tool for the high-level description of interactions, communications, and ...
developed at
INRIA
The National Institute for Research in Digital Science and Technology (Inria) () is a French national research institution focusing on computer science and applied mathematics.
It was created under the name ''Institut de recherche en informatiq ...
. The join-calculus was developed to provide a formal basis for the design of distributed programming languages, and therefore intentionally avoids communications 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
In theoretical computer science, the -calculus (or pi-calculus) is a process calculus. The -calculus allows channel names to be communicated along the channels themselves, and in this way it is able to describe concurrent computations whose netw ...
. 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
In theoretical computer science, the -calculus (or pi-calculus) is a process calculus. The -calculus allows channel names to be communicated along the channels themselves, and in this way it is able to describe concurrent computations whose netw ...
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
CLIPS is a public domain software tool for building expert systems. The name is an acronym for "C Language Integrated Production System." The syntax and name were inspired by Charles Forgy's OPS5. The first versions of CLIPS were developed st ...
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
*
Polyphonic C# and its successor
Cω extend
C#
* MC# and Parallel C# extend Polyphonic C#
*
Join Java extends
Java
Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's mos ...
* A Concurrent Basic proposal that uses Join-calculus
* JErlang (the J is for Join, erjang is Erlang for the JVM)
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:
* The ScalaJoins and th
Chymystlibraries are in
Scala
JoinHsby Einar Karttunen an
syallop/Join-Languageby Samuel Yallop are DSLs for Join calculus in
Haskell
* Joinads - various implementations of join calculus in
F#
* CocoaJoin is an experimental implementation in
Objective-C
Objective-C is a general-purpose, object-oriented programming language that adds Smalltalk-style messaging to the C programming language. Originally developed by Brad Cox and Tom Love in the early 1980s, it was selected by NeXT for its NeXT ...
for iOS and Mac OS X
* The Join Python library is in
Python 3
The programming language Python was conceived in the late 1980s, and its implementation was started in December 1989 by Guido van Rossum at CWI in the Netherlands as a successor to ABC capable of exception handling and interfacing with th ...
* C++ via Boost
Yigong Liu - Join-Asynchronous Message Coordination and Concurrency Library
/ref> (for boost from 2009, ca. v. 40, current (Dec '19) is 72).
References
External links
* INRIA
Join Calculus homepage
* Microsoft Research
The Join Calculus: a Language for Distributed Mobile Programming
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Process calculi