Elixir (programming language)

History

José Valim is the creator of the Elixir programming language, a research and development project of Plataformatec. His goals were to enable higher extensibility and productivity in the Erlang VM while keeping compatibility with Erlang's ecosystem.^[23][24]

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.^[25]

On July 12, 2018, Honeypot released a mini-documentary on Elixir.^[26]

Versioning

Elixir mostly^[27] 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.^[28]

Features

• Compiles to bytecode for the Erlang Virtual Machine (BEAM)^[29]
• Everything is an expression^[29]
• 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)^[29]
• 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^[29]
• Shared nothing concurrent programming via message passing (Actor model)^[30]
• Emphasis on recursion and higher-order functions instead of side-effect-based looping
• Lightweight concurrency utilizing Erlang's mechanisms^[29]
• Railway oriented programming via the with construct^[31]
• Built-in tooling for managing dependencies, code compilation, running tests, formatting code, remote debugging and more
• Lazy and async collections with streams
• Pattern matching^[29] to promote assertive code^[32]
• 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.^[33]
• Phoenix is a web development framework written in Elixir which implements the server-side Model View Controller (MVC) pattern.^[34]

See also

• Concurrent computing
• Distributed computing

References

External links

• Elixir language website