Elixir (programming language)

Elixir

Paradigm	multi-paradigm: functional, concurrent, distributed, process-oriented
First appeared	2012
Stable release	1.2.5 / 30 April 2016[1]
Typing discipline	dynamic, strong
Platform	Erlang
License	Apache License 2.0[2]
Filename extensions	.ex, .exs
Website	elixir-lang.org
Influenced by
Erlang, LFE, Ruby, Clojure
Influenced
LFE

Elixir is a functional, concurrent, general-purpose programming language that runs on the Erlang virtual machine (BEAM). Elixir builds on top of Erlang to provide distributed, fault-tolerant, soft real-time, non-stop applications but also extends it to support metaprogramming with macros and polymorphism via protocols.^[3]

History

José Valim is the creator of the Elixir programming language, a R&D project of Plataformatec. His goals were to enable higher extensibility and productivity in the Erlang VM while keeping compatibility with Erlang's tools and ecosystem.^[4]

Features

• A language that compiles to bytecode for the Erlang Virtual Machine (BEAM)^[5]
• Everything is an expression^[5]
• Erlang functions can be called from Elixir without run time impact, due to compilation to Erlang bytecode, and vice versa
• Meta programming allowing direct manipulation of AST^[5]
• Polymorphism via a mechanism called protocols. Like 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^[5]
• Shared nothing concurrent programming via message passing (Actor model)^[6]
• Emphasis on recursion and higher-order functions instead of side-effect-based looping
• Lightweight concurrency utilizing Erlang's mechanisms.^[5]
• Lazy and async collections with streams
• Pattern matching^[5]
• 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

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

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

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
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

References

1. "elixir/CHANGELOG.md at v1.2.5 · elixir-lang/elixir · GitHub". GitHub.
2. "elixir/LICENSE at master · elixir-lang/elixir · GitHub". GitHub.
3. "Elixir". José Valim. Retrieved 2013-02-17.
4. "Elixir - A modern approach to programming for the Erlang VM". Retrieved 2013-02-17.
5. "Elixir". Retrieved 2014-09-07.
6. Loder, Wolfgang (12 May 2015). Erlang and Elixir for Imperative Programmers. "Chapter 16: Code Structuring Concepts", section title "Actor Model": Leanpub. Retrieved 7 July 2015.

External links

• Elixir language website
• Code on GitHub
• Elixir - A modern approach to programming for the Erlang VM video presentation
• Dave Thomas: "Programming Elixir 1.2: Functional → Concurrent → Pragmatic → Fun" (book)
• Simon St. Laurent, J. David Eisenberg: "Introducing Elixir" (book)
• Chris McCord: "Metaprogramming Elixir " (book)
• Joe Armstrong: "A Week with Elixir" (blog entry)