Elixir (programming language)

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

Elixir is aimed at large-scale sites and apps. It uses features of Ruby, Erlang, and Clojure to develop a high-concurrency and low-latency language. It was designed to handle large data volumes. Elixir is also used in telecommunications, e-commerce, and finance.

In 2021, the Numerical Elixir effort was announced with the goal of bringing machine learning, neural networks, GPU compilation, data processing, and computational notebooks to the Elixir ecosystem.

• Compiles to bytecode for the BEAM virtual machine of Erlang. Full interoperability with Erlang code, without runtime impact.
• Scalability and fault-tolerance, thanks to Erlang's lightweight concurrency mechanisms
• Built-in tooling for managing dependencies, code compilation, running tests, formatting code, remote debugging and more.
• An interactive REPL inside running programs, including Phoenix web servers, with code reloading and access to internal state
• Everything is an expression
• Pattern matching to promote assertive code
• Type hints for static analysis tools
• Immutable data, with an emphasis, like other functional languages, on recursion and higher-order functions instead of side-effect-based looping
• Shared nothing concurrent programming via message passing (actor model)
• Lazy and async collections with streams
• Railway-oriented programming via the with construct
• Hygienic metaprogramming by direct access to the abstract syntax tree (AST). Libraries often implement small domain-specific languages, such as for databases or testing.
• Code execution at compile time. The Elixir compiler also runs on the BEAM, so modules that are being compiled can immediately run code which has already been compiled.
• Polymorphism via a mechanism called protocols. Dynamic dispatch, as in Clojure, however, without multiple dispatch because Elixir protocols dispatch on a single type.
• Support for documentation via Python-like docstrings in the Markdown formatting language
• Unicode support and UTF-8 strings

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!

Pipe operator:

iex> "Elixir" |> String.graphemes() |> Enum.frequencies() %{"E" => 1, "i" => 2, "l" => 1, "r" => 1, "x" => 1} iex> %{values: 1..5} |> Map.get(:values) |> Enum.map(& &1 * 2) [2, 4, 6, 8, 10] iex> %{values: 1..5} |> Map.get(:values) |> Enum.map(& &1 * 2) |> Enum.sum() 30

Pattern matching (a.k.a. destructuring):

iex> %{left: x} = %{left: 5, right: 8} iex> x 5 iex> {:ok, [_ | rest]} = {:ok, [1, 2, 3]} iex> rest [2, 3]

Pattern matching with 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

List comprehension:

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

Asynchronously reading files with streams:

1..5 |> Task.async_stream(&File.read!("#{&1}.txt")) |> Stream.filter(fn {:ok, contents} -> String.trim(contents) != "" end) |> Enum.join("\n")

Multiple function bodies with guards:

def fib(n) when n in [0, 1], do: n def fib(n), do: fib(n-2) + fib(n-1)

Relational databases with the Ecto library:

schema "weather" do field :city # Defaults to type :string field :temp_lo, :integer field :temp_hi, :integer field :prcp, :float, default: 0.0 end Weather |> where(city: "Kraków") |> order_by(:temp_lo) |> limit(10) |> Repo.all

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