Erlang (programming language)

Erlang (/ˈɜːrlæŋ/ ER-lang) is a general-purpose, concurrent, garbage-collected programming language and runtime system. The sequential subset of Erlang is almost a functional language (excluding certain built-in functions), with eager evaluation, single assignment, and dynamic typing. It was originally designed by Ericsson to support distributed, fault-tolerant, soft real-time, highly available, non-stop applications. It supports hot swapping, thus code can be changed without stopping a system.

While threads require external library support in most languages, Erlang provides language-level features for creating and managing processes with the aim of simplifying concurrent programming. Though all concurrency is explicit in Erlang, processes communicate using message passing instead of shared variables, which removes the need for explicit locks (a locking scheme is still used internally by the VM).

The first version was developed by Joe Armstrong, Robert Virding and Mike Williams in 1986. It was originally a proprietary language within Ericsson, but was released as open source in 1998. Erlang, along with OTP, a collection of middleware and libraries in Erlang, are now supported and maintained by the OTP product unit at Ericsson and widely referred to as Erlang/OTP.