Elixir (programming language)

Elixir

Paradigm	multi-paradigm: functional, concurrent, process-oriented, homoiconic
First appeared	2012
Stable release	1.0.4
Typing discipline	dynamic, strong
Platform	Erlang
License	Apache License
Filename extensions	.ex, .exs
Website	elixir-lang.org
Influenced by Erlang, Ruby, Clojure

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.^[1]

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.^[2]

Features

• A language that compiles to bytecode for the Erlang Virtual Machine (BEAM)^[3]
• Everything is an expression^[3]
• 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^[3]
• Polymorphism via a mechanism called protocols. Enumerable is an example of a protocol, and is inspired by Clojure reducers^[4]
• Support for documentation via Python-like docstrings in the Markdown formatting language^[3]
• 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 with simplified syntax (e.g. Task)^[3]
• Lazy and async collections with streams
• Pattern matching^[3]
• 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:

IO.puts "Hello World!"

Comprehensions

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

Pattern Matching

[1, a] = [1, 2]
# 'a' now equals 2
 
{:ok, [hello: a]} = {:ok, [hello: "world"]}
# 'a' now equals "world"

Modules

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

References

External links

• Elixir language website
• Code on GitHub
• Elixir - A modern approach to programming for the Erlang VM video presentation
• Dave Thomas: "Programming Elixir: 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)