Writing and Publishing Elixir Libraries

In this talk, we’ll walk through the process of writing and publishing an Elixir library from scratch. Along the way, we’ll discover a handful of Elixir features such as: Mix, Documentation, Doctests, Typespecs, and Hex.

Transcript

1. A practical guide to Writing & Publishing Elixir Libraries Yos Riady yos.io goo.gl/PVekCF
3. At this moment, there are more than 7100 gems hosted on Rubygems.org. Hex.pm has 1455 packages.
5. Introduction to Elixir Elixir’s build tool Background Mix Docs Types Conclusion Docstrings and Doctests Summary and further learning Introduction to Typespecs
6. What is Elixir? • Language that compiles to Erlang • Built on top of the famed Erlang VM (“nine 9s of reliability”) ◦ Traditionally used for telecommunications by Ericsson ◦ WhatsApp, Facebook Messenger, Riot Games, RabbitMQ, Riak
7. Features of Elixir • A pleasant, modern syntax similar to Ruby • Immutable • Pattern Matching • Gradual types with Typespecs • First-class documentation • Metaprogramming through Macros • Concurrency abstractions (Actor model and OTP) • Interop with Erlang
8. Introduction to Elixir Elixir’s build tool Background Mix Docs Types Conclusion Docstrings and Doctests Summary and further learning Introduction to Typespecs
9. Mix is Elixir’s build tool
10. Use Mix to generate an Elixir project > mix new simple_statistics > cd simple_statistics
11. Elixir project structure |-- _build |-- config/ |-- config.exs |-- lib/ |-- simple_statistics.ex |-- test/ |-- simple_statistics_test.exs |-- test_helper.exs |-- mix.exs |-- mix.lock |-- README.md |-- .gitignore
12. defmodule SimpleStatistics.Mixfile do use Mix.Project def project do [app: :simple_statistics, deps: deps] end defp deps do [{:ex_doc, "~> 0.11", only: :dev}, {:dialyxir, "~> 0.3", only: [:dev]}] end end Mix.exs defines our project metadata
13. Write code in lib/ # lib/simple_statistics/mean.ex defmodule SimpleStatistics.Mean do def mean(list) do Enum.sum(list) / Kernel.length(list) end end
14. Introduction to Elixir Elixir’s build tool Background Mix Docs Types Conclusion Docstrings and Doctests Summary and further learning Introduction to Typespecs
15. First-class documentation
16. Document with Docstrings # lib/simple_statistics/mean.ex defmodule SimpleStatistics.Mean do @doc ~S""" The mean is the sum of all values over the number of values. """ def mean([]), do: nil ... end
17. # test/simple_statistics_test.ex defmodule SimpleStatisticsTest do use ExUnit.Case test "the truth" do assert 1 + 1 == 2 end end Write unit tests in test/ with ExUnit
18. Show examples with Doctests @doc ~S""" The mean is the sum of all values over the number of values. ## Examples iex> SimpleStatistics.Mean.mean([]) nil iex> SimpleStatistics.Mean.mean([1,2,3,4,5]) 3.0 iex> SimpleStatistics.Mean.mean([1.5,-2.1,3,4.5,5]) 2.38 """
19. # test/simple_statistics_test.ex defmodule SimpleStatisticsTest do use ExUnit.Case doctest SimpleStatistics.Mean end Doctests can be run as tests
20. Run tests with Mix > mix test . Finished in 0.07 seconds (0.07s on load, 0.00s on tests) 1 test, 0 failures
21. Introduction to Elixir Elixir’s build tool Background Mix Docs Types Conclusion Docstrings and Doctests Summary and further learning Introduction to Typespecs
22. Types
23. Typespecs @spec add(number, number) :: number def add(x, y) do x + y end @spec mean(nonempty_list(number)) :: float() def mean(list) do Enum.sum(list) / Kernel.length(list) end
24. Typespecs • Scalars: integer(), float(), pos_integer() • Lists: list(type), non_empty_list(type), [type] • Functions: (type1, type2 -> type) • Create your own types: @type t :: %ECS.Entity{ id: String.t, components: [ECS.Component] }
25. Generate web-ready documentation with ex_doc # mix.exs defp deps do [{:ex_doc, "~> 0.11", only: :dev}, {:earmark, "~> 0.1", only: :dev}] end
26. mix docs to generate documentation
28. Introduction to Elixir Elixir’s build tool Background Mix Docs Types Conclusion Docstrings and Doctests Summary and further learning Introduction to Typespecs
29. Summary • Mix • Documentation & Docstrings • Tests & Doctests • Typespecs • Hex
30. Thanks Yos Riady yos.io
31. A practical guide to Writing & Publishing Elixir Libraries Yos Riady yos.io goo.gl/PVekCF