Elixir (programming language)

Short description: Programming language running on the Erlang virtual machine

Elixir

Paradigm	multi-paradigm: functional, concurrent, distributed, process-oriented
First appeared	2012 (2012)
Typing discipline	dynamic, strong, duck
Platform	Erlang
License	Apache License 2.0
Filename extensions	.ex, .exs
Website	elixir-lang.org
Influenced by
Clojure, Erlang, Ruby
Influenced
LFE

Elixir is a functional, concurrent, general-purpose programming language that runs on the BEAM virtual machine which is also used to implement the Erlang programming language. Elixir builds on top of Erlang and shares the same abstractions for building distributed, fault-tolerant applications. Elixir also provides productive tooling and an extensible design. The latter is supported by compile-time metaprogramming with macros and polymorphism via protocols.

Elixir is used by companies such as Ramp, PagerDuty, Discord, Brex, E-MetroTel, Pinterest, Moz, Bleacher Report, The Outline, Inverse, Divvy, FarmBot and for building embedded systems. The community organizes yearly events in the United States, Europe and Japan as well as minor local events and conferences.

History

José Valim is the creator of the Elixir programming language, a research and development project created at Plataformatec. His goals were to enable higher extensibility and productivity in the Erlang VM while keeping compatibility with Erlang's ecosystem.

José Valim aimed to create a programming language for large-scale sites and apps. Being a Ruby developer, he used features of Ruby, Erlang, and Clojure to develop a high-concurrency and low-latency language. Elixir was designed to handle large data volumes. Its speed and capabilities spread Elixir in telecommunication, eCommerce, and finance industries.

On July 12, 2018, Honeypot released a mini-documentary on Elixir.

Versioning

Elixir mostly follows semantic versioning and has only 1 major version with no plans for a second. Each of the minor versions supports a specific range of Erlang/OTP versions.

Features

• Compiles to bytecode for the Erlang Virtual Machine (BEAM)
• Everything is an expression
• Erlang functions can be called from Elixir, and vice versa, without run time impact, due to compilation to Erlang bytecode
• Meta programming allowing direct manipulation of abstract syntax tree (AST)
• Polymorphism via a mechanism called protocols. As in Clojure, protocols provide a dynamic dispatch mechanism. However, this is not to be confused with multiple dispatch as Elixir protocols dispatch on a single type.
• Support for documentation via Python-like docstrings in the Markdown formatting language
• Shared nothing concurrent programming via message passing (Actor model)
• Emphasis on recursion and higher-order functions instead of side-effect-based looping
• Lightweight concurrency utilizing Erlang's mechanisms
• Railway oriented programming via the with construct
• Built-in tooling for managing dependencies, code compilation, running tests, formatting code, remote debugging and more
• Lazy and async collections with streams
• Pattern matching to promote assertive code
• Unicode support and UTF-8 strings

Examples

The following examples can be run in an iex shell or saved in a file and run from the command line by typing elixir <filename>.

Classic Hello world example:

iex> IO.puts("Hello World!")
Hello World!

Comprehensions

iex> for n <- [1,2,3,4,5], rem(n, 2) == 1, do: n*n
[1, 9, 25]

Pattern Matching (destructuring)

iex> [1, a] = [1, 2]
iex> a
2

iex> {:ok, [hello: a]} = {:ok, [hello: "world"]}
iex> a
"world"

Pattern Matching (multiple clauses)

iex> case File.read("path/to/file") do
iex>   {:ok, contents} -> IO.puts("found file: #{contents}")
iex>   {:error, reason} -> IO.puts("missing file: #{reason}")
iex> end

Pipe Operator

iex> "1" |> String.to_integer() |> Kernel.*(2)
2

Modules

defmodule Fun do
  def fib(0), do: 0
  def fib(1), do: 1
  def fib(n), do: fib(n-2) + fib(n-1)  
end

Sequentially spawning a thousand processes

for num <- 1..1000, do: spawn fn -> IO.puts("#{num * 2}") end

Asynchronously performing a task

task = Task.async fn -> perform_complex_action() end
other_time_consuming_action()
Task.await task

Noteworthy Elixir projects

• Mix is a build automation tool that provides tasks for creating, compiling, and testing Elixir projects, managing its dependencies, and more.
• Phoenix is a web development framework written in Elixir which implements the server-side Model View Controller (MVC) pattern.

See also

• Concurrent computing
• Distributed computing

External links

• Elixir language website