ExDoc

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ExDoc is a tool to generate documentation for your Elixir projects. To see an example, you can access Elixir's official docs.

To learn about how to document your projects, see Elixir's writing documentation page.

To see all supported options, see the documentation for mix docs.

Features

ExDoc ships with many features:

Using ExDoc with Mix

To use ExDoc in your Mix projects, first add ExDoc as a dependency.

If you are using Elixir v1.10, or later:

def deps do
  [
    {:ex_doc, "~> 0.24", only: :dev, runtime: false},
  ]
end

If you are using Elixir v1.7, v1.8, or v1.9:

def deps do
  [
    {:ex_doc, "~> 0.22.0", only: :dev, runtime: false},
  ]
end

If you are using Elixir v1.6, or earlier:

def deps do
  [
    {:ex_doc, "~> 0.18.0", only: :dev, runtime: false},
  ]
end

After adding ExDoc as a dependency, run mix deps.get to install it.

ExDoc will automatically pull in information from your projects, like the application and version. However, you may want to set :name, :source_url and :homepage_url to have a nicer output from ExDoc, such as:

def project do
  [
    app: :my_app,
    version: "0.1.0-dev",
    deps: deps(),

    # Docs
    name: "MyApp",
    source_url: "https://github.com/USER/PROJECT",
    homepage_url: "http://YOUR_PROJECT_HOMEPAGE",
    docs: [
      main: "MyApp", # The main page in the docs
      logo: "path/to/logo.png",
      extras: ["README.md"]
    ]
  ]
end

Now you are ready to generate your project documentation with mix docs. To see all options available when generating docs, run mix help docs.

Using ExDoc via command line

You can ExDoc via the command line as follows:

  1. Install ExDoc as an escript: 

    $ mix escript.install hex ex_doc

  2. Then you are ready to use it in your projects. First, move into your project directory and make sure it is already compiled: 

    $ cd PATH_TO_YOUR_PROJECT
$ mix compile

  3. Next invoke the ex_doc executable from your project: 

    $ ex_doc "PROJECT_NAME" "PROJECT_VERSION" path/to/project/ebin -m "PROJECT_MODULE" -u "https://github.com/GITHUB_USER/GITHUB_REPO" -l path/to/logo.png

For example, here are some acceptable values:

PROJECT_NAME    => Ecto
PROJECT_VERSION => 0.1.0
PROJECT_MODULE  => Ecto (the main module provided by the library)
GITHUB_USER     => elixir-lang
GITHUB_REPO     => ecto

Using ExDoc with Erlang projects

ExDoc is capable of generating documentation from Erlang's edoc annotations through the following steps:

  1. Use Erlang/OTP 24+

  2. Add the following to your rebar.config. This instructs edoc to generate doc chunks instead of HTML docs: 

    {edoc_opts, [
  {doclet, edoc_doclet_chunks},
  {layout, edoc_layout_chunks},
  {dir, "_build/default/lib/<app>/doc"}]}.

    Replace <app> with the name of your app.

  3. Install ExDoc escript: 

    $ mix escript.install hex ex_doc
$ ex_doc --version

    Make sure escript is in your system path, otherwise point to it directly.

  4. Generate docs: 

    $ rebar3 edoc
$ ex_doc "PROJECT_NAME" "PROJECT_VERSION" _build/default/lib/<app>/ebin

  5. If you're publishing docs to Hex.pm, first add the following to your src/<app>.app.src: 

    {doc, "doc"}

    This instructs rebar3 to get HTML docs from the directory "doc" and that's where ExDoc would generate the docs by default.

    Now you can publish your docs: 

    $ rebar3 hex docs

  6. If your project has dependencies and you want to generate links to them, you need to add the dependencies to the code path.

    Suppose you're building foo that depends on bar and baz. Generate the docs with: 

    $ ex_doc "foo" "1.0.0" "_build/default/lib/foo/ebin" \
    --paths "_build/default/lib/*/ebin"

Auto-linking

ExDoc for Elixir will automatically generate links across modules and functions if you enclose them in backticks:

ExDoc supports linking to modules (`MyModule`), functions (`MyModule.function/1`), types (`t:MyModule.type/2`) and callbacks (`c:MyModule.callback/3`). If you want to link a function, type or callback in the current module, you may skip the module name, such as `function/1`.

You can also use a custom text, e.g.: [custom text](`MyModule.function/1`). This also allows to refer to OTP modules, e.g.: [`:array`](`:array`).

Link to extra pages like this: [Up and running](Up and running.md) (skipping the directory the page is in), the final link will be automatically converted to up-and-running.html.

Contributing

The easiest way to test changes to ExDoc is to locally rebuild the app and its own documentation:

  1. Run mix setup to install all dependencies
  2. Run mix build to generate docs. This is a custom alias that will build assets, recompile ExDoc, and output fresh docs into the doc/ directory
  3. If you want to contribute a pull request, please do not add to your commits the files generated in the assets/ and formatters/ folders
  4. Run mix lint to check if the Elixir and JavaScript files are properly formatted. You can run mix fix to let the JavaScript linter and Elixir formatter fix the code automatically before submitting your pull request

License

ExDoc source code is released under Apache 2 License. The generated contents, however, are under different licenses based on projects used to help render HTML, including CSS, JS, and other assets.

Any documentation generated by ExDoc, or any documentation generated by any "Derivative Works" (as specified in the Apache 2 License), must include a direct, readable, and visible link to the ExDoc repository on each rendered material. For HTML pages, a rendered material represents every single page. For PDF, EPUB and other ebook formats, it means one entry for the whole material.