Elixir (programming language) explained

Elixir
Logo Caption:	Elixir
Paradigms:	multi-paradigm functional, concurrent, distributed, process-oriented
Typing:	dynamic, strong
Influenced:	Gleam, LFE
Platform:	Erlang
License:	Apache License 2.0^[1]
Influenced By:	Clojure, Erlang, Ruby
Designer:	José Valim
File Ext:	.ex, .exs

Elixir is a functional, concurrent, high-level general-purpose programming language that runs on the BEAM virtual machine, which is also used to implement the Erlang programming language.^[2] Elixir builds on top of Erlang and shares the same abstractions for building distributed, fault-tolerant applications. Elixir also provides tooling and an extensible design. The latter is supported by compile-time metaprogramming with macros and polymorphism via protocols.^[3]

The community organizes yearly events in the United States,^[4] Europe,^[5] and Japan,^[6] as well as minor local events and conferences.^{[7] [8]}

History

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.^{[9] [10]}

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.^[11]

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.^[12]

Versioning

Each of the minor versions supports a specific range of Erlang/OTP versions. The current stable release version is .

Features

• Compiles to bytecode for the BEAM virtual machine of Erlang.^[13] 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^[14]
• 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)^[15]
• Lazy and async collections with streams
• Railway oriented programming via the with construct^[16]
• 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

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!

Pipe operator:iex> "Elixir" |> String.graphemes |> Enum.frequencies%

iex> % |> Map.get(:values) |> Enum.map(& &1 * 2)[2, 4, 6, 8, 10]

iex> |> Enum.sum30Pattern matching (a.k.a. destructuring):iex> % = %iex> x5

iex> = iex> rest[2, 3]

Pattern matching with multiple clauses:iex> case File.read("path/to/file") doiex> -> IO.puts("found file: #")iex> -> IO.puts("missing file: #")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!("#.txt"))|> Stream.filter(fn -> String.trim(contents) != "" end)|> Enum.join("\n")

Multiple function bodies with guards:def fib(n) when n in [0, 1], do: ndef 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: 0.0end

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("#") end

Asynchronously performing a task:task = Task.async fn -> perform_complex_action endother_time_consuming_actionTask.await task

See also

• Concurrent computing
• Distributed computing
• Parallel computing

Further reading

• Book: Simon St. Laurent . J. Eisenberg . December 22, 2016 . Introducing Elixir: Getting Started in Functional Programming 2nd Edition. . 978-1491956779 . en.
• Book: Sasa Juric . January 12, 2019 . Elixir in Action 2nd Edition . . 978-1617295027 . en.

Notes and References

1. Web site: elixir/LICENSE at master · elixir-lang/elixir · GitHub. GitHub.
2. News: Most Popular Programming Languages of 2018 - Elite Infoworld Blog. 2018-03-30. 2018-05-08. 2018-05-09. https://web.archive.org/web/20180509080342/https://www.eliteinfoworld.com/blog/popular-programming-languages-2018/. dead.
3. Web site: Elixir . José Valim . 2013-02-17.
4. Web site: ElixirConf. 2018-07-11.
5. Web site: ElixirConf. 2018-07-11.
6. Web site: Erlang & Elixir Fest. 2019-02-18.
7. Web site: Elixir LDN. 2018-07-12.
8. Web site: EMPEX - Empire State Elixir Conference. 2018-07-12.
9. Elixir - A modern approach to programming for the Erlang VM . 2013-02-17.
10. José Valim - ElixirConf EU 2017 Keynote . https://ghostarchive.org/varchive/youtube/20211117/IZvpKhA6t8A. 2021-11-17 . live. 2017-07-14.
11. Web site: Behinde the code: The One Who Created Elixir . 2019-11-25.
12. Web site: Numerical Elixir (Nx). . 2024-05-06.
13. Web site: Elixir . 2014-09-07.
14. Web site: 24 September 2014 . Writing assertive code with Elixir . 2018-07-05.
15. Book: Loder . Wolfgang . Erlang and Elixir for Imperative Programmers . 12 May 2015 . Leanpub . "Chapter 16: Code Structuring Concepts", section title "Actor Model" . 7 July 2015.
16. Web site: Wlaschin . Scott . May 2013 . Railway Oriented Programming . live . https://web.archive.org/web/20210130221804/http://fsharpforfunandprofit.com/rop/ . 30 January 2021 . 28 February 2021 . F# for Fun and Profit.