Joule is a capability-secure massively-

concurrent Concurrent means happening at the same time. Concurrency, concurrent, or concurrence may refer to: Law * Concurrence, in jurisprudence, the need to prove both ''actus reus'' and ''mens rea'' * Concurring opinion (also called a "concurrence"), a ...

dataflow programming In computer programming, dataflow programming is a programming paradigm that models a program as a directed graph of the data flowing between operations, thus implementing dataflow principles and architecture. Dataflow programming languages share s ...

language, designed for building distributed applications. It is so concurrent that the order of statements within a block is irrelevant to the operation of the block. Statements are executed whenever possible, based on their inputs. Everything in Joule happens by sending messages. There is no

control flow In computer science, control flow (or flow of control) is the order in which individual statements, instructions or function calls of an imperative program are executed or evaluated. The emphasis on explicit control flow distinguishes an ''im ...

. Instead, the programmer describes the flow of data, making it a

language. Joule development started in 1994 at ''Agorics'' in

Palo Alto, California Palo Alto (; Spanish for "tall stick") is a charter city in the northwestern corner of Santa Clara County, California, United States, in the San Francisco Bay Area, named after a coastal redwood tree known as El Palo Alto. The city was es ...

. It is considered the precursor to the

E programming language E is an object-oriented programming language for secure distributed computing, created by Mark S. Miller, Dan Bornstein, Douglas Crockford, Chip Morningstar and others at Electric Communities in 1997. E is mainly descended from the concurrent ...

Language syntax

Numerals A numeral is a figure, symbol, or group of figures or symbols denoting a number. It may refer to: * Numeral system used in mathematics * Numeral (linguistics), a part of speech denoting numbers (e.g. ''one'' and ''first'' in English) * Numerical d ...

consist of

ASCII ASCII ( ), abbreviated from American Standard Code for Information Interchange, is a character encoding standard for electronic communication. ASCII codes represent text in computers, telecommunications equipment, and other devices. Because ...

digits 0–9; identifiers are

Unicode Unicode, formally The Unicode Standard,The formal version reference is is an information technology standard for the consistent encoding, representation, and handling of text expressed in most of the world's writing systems. The standard, wh ...

sequences of digits, letters, and operator characters that begin with a letter. It is also possible to form identifiers by using Unicode sequences (including whitespace) enclosed by either straight (' ') or standard (‘ ’) single quotes, where the backslash is the escape character.

Keyword Keyword may refer to: Computing * Keyword (Internet search), a word or phrase typically used by bloggers or online content creator to rank a web page on a particular topic * Index term, a term used as a keyword to documents in an information syst ...

s have to start with a letter, except the ''•'' keyword to send information.

Operators Operator may refer to: Mathematics * A symbol indicating a mathematical operation * Logical operator or logical connective in mathematical logic * Operator (mathematics), mapping that acts on elements of a space to produce elements of another sp ...

consist of Unicode sequences of digits, letters, and operator characters, beginning with an operator character.

Labels A label (as distinct from signage) is a piece of paper, plastic film, cloth, metal, or other material affixed to a container or product, on which is written or printed information or symbols about the product or item. Information printed d ...

are identifiers followed by a colon (':'). At the root, Joule is an imperative language and because of that a statement-based language. It has a rich expression syntax, which transforms easily to its relational syntax underneath. Complex expressions become separate statements, where the site of the original expression is replaced by a reference to the acceptor of the results channel. Therefore, nested expressions still compute completely concurrently with their embedding statement. If amount <= balance • account withdraw: amount else • account report-bounce: end An identifiers may name a channel to communicate with the server. If this is the case, it is said to be ''bound'' to that channel.

References

External links

Joule: Distributed Application Foundations

C2: Promise Pipelining
Concurrent programming languages Object-oriented programming languages Secure programming languages Capability systems {{compu-lang-stub