Guide

# Package Guide

## Installation

Documenter is a registered package and so can be installed via Pkg.add.

Pkg.add("Documenter")

This package supports Julia 0.6 and 0.7-dev.

## Usage

Documenter is designed to do one thing – combine markdown files and inline docstrings from Julia's docsystem into a single inter-linked document. What follows is a step-by-step guide to creating a simple document.

### Setting up the folder structure

Firstly, we need a Julia module to document. This could be a package generated via PkgDev.generate or a single .jl script accessible via Julia's LOAD_PATH. For this guide we'll be using a package called Example.jl that has the following directory layout:

Example/
src/
Example.jl
...

Note that the ... just represent unimportant files and folders.

We must decide on a location where we'd like to store the documentation for this package. It's recommended to use a folder named docs/ in the toplevel of the package, like so

Example/
docs/
...
src/
Example.jl
...

Inside the docs/ folder we need to add two things. A source folder which will contain the markdown files that will be used to build the finished document and a Julia script that will be used to control the build process. The following names are recommended

docs/
src/
make.jl

### Building an empty document

With our docs/ directory now setup we're going to build our first document. It'll just be a single empty file at the moment, but we'll be adding to it later on.

Add the following to your make.jl file

using Documenter, Example

makedocs()

This assumes you've installed Documenter as discussed in Installation and that your Example.jl package can be found by Julia.

Note

If your source directory is not accessible through Julia's LOAD_PATH, you might wish to add the following line at the top of make.jl

push!(LOAD_PATH,"../src/")

Now add an index.md file to the src/ directory. The name has no particular significance though and you may name it whatever you like. We'll stick to index.md for this guide.

Leave the newly added file empty and then run the following command from the docs/ directory

$julia make.jl Note that $ just represents the prompt character. You don't need to type that.

If you'd like to see the output from this command in color use

\$ julia --color=yes make.jl

When you run that you should see the following output

Documenter: setting up build directory.
Documenter: expanding markdown templates.
Documenter: building cross-references.
Documenter: running document checks.
Documenter: rendering document.
Documenter: populating indices.
Documenter: copying assets to build directory.

The docs/ folder should contain a new directory – called build/. It's structure should look like the following

build/
assets/
Documenter.css
mathjaxhelper.js
index.md
Warning

Never git commit the contents of build (or any other content generated by Documenter) to your repository's master branch. Always commit generated files to the gh-pages branch of your repository. This helps to avoid including unnecessary changes for anyone reviewing commits that happen to include documentation changes.

See the Hosting Documentation section for details regarding how you should go about setting this up correctly.

At the moment build/index.md should be empty since src/index.md is empty.

At this point you can add some text to src/index.md and rerun the make.jl file to see the changes if you'd like to.

### Adding some docstrings

Next we'll splice a docstring defined in the Example module into the index.md file. To do this first document a function in that module:

module Example

export func

"""
func(x)

Returns double the number x plus 1.
"""
func(x) = 2x + 1

end

Then in the src/index.md file add the following

# Example.jl Documentation

@docs
func(x)


When we next run make.jl the docstring for Example.func(x) should appear in place of the @docs block in build/index.md. Note that more than one object can be referenced inside a @docs block – just place each one on a separate line.

Note that a @docs block is evaluated in the Main module. This means that each object listed in the block must be visible there. The module can be changed to something else on a per-page basis with a @meta block as in the following

# Example.jl Documentation

@meta
CurrentModule = Example


@docs
func(x)


#### Filtering Included Docstrings

In some cases you may want to include a docstring for a Method that extends a Function from a different module – such as Base. In the following example we extend Base.length with a new definition for the struct T and also add a docstring:

struct T
# ...
end

"""
Custom length docs for T.
"""
Base.length(::T) = 1

When trying to include this docstring with

@docs
length


all the docs for length will be included – even those from other modules. There are two ways to solve this problem. Either include the type in the signature with

@docs
length(::T)


or declare the specific modules that makedocs should include with

makedocs(
# options
modules = [MyModule]
)

### Cross Referencing

It may be necessary to refer to a particular docstring or section of your document from elsewhere in the document. To do this we can make use of Documenter's cross-referencing syntax which looks pretty similar to normal markdown link syntax. Replace the contents of src/index.md with the following

# Example.jl Documentation

@docs
func(x)


- link to [Example.jl Documentation](@ref)
- link to [func(x)](@ref)

So we just have to replace each link's url with @ref and write the name of the thing we'd link to cross-reference. For document headers it's just plain text that matches the name of the header and for docstrings enclose the object in backticks.

This also works across different pages in the same way. Note that these sections and docstrings must be unique within a document.

### Navigation

Documenter can auto-generate tables of contents and docstring indexes for your document with the following syntax. We'll illustrate these features using our index.md file from the previous sections. Add the following to that file

# Example.jl Documentation

@contents


## Functions

@docs
func(x)


## Index

@index


The @contents block will generate a nested list of links to all the section headers in the document. By default it will gather all the level 1 and 2 headers from every page in the document, but this can be adjusted using Pages and Depth settings as in the following

@contents
Pages = ["foo.md", "bar.md"]
Depth = 3


The @index block will generate a flat list of links to all the docs that that have been spliced into the document using @docs blocks. As with the @contents block the pages to be included can be set with a Pages = [...] line. Since the list is not nested Depth is not supported for @index.

## Output formats

Documenter produces a set of Markdown files, which then have to be converted into a user-readable format for distribution. While in principle any Markdown parser would do (as long as it supports the required Markdown extensions), the Python-based MkDocs is usually used to convert the Markdown files into a set of HTML pages. See Hosting Documentation for further information on configuring MkDocs for Documenter.

Native HTML output

There is experimental support for native HTML output in Documenter. It can be enabled by passing the format = :html option to makedocs. It also requires the pages and sitename options. make.jl should then look something like

makedocs(
...,
format = :html,
sitename = "Package name",
pages = [
"page.md",
"Page title" => "page2.md",
"Subsection" => [
...
]
]
)

deploydocs(
repo   = "github.com/USER/PKG.jl.git",
target = "build",
deps   = nothing,
make   = nothing
)

Since Documenter's docs are already built using HTML output, a fully working example of the configuration can be found in docs/make.jl. Note that with this configuration, mkdocs.yml is not required.

It is still under development, may contain bugs, and undergo changes. However, any feedback is very welcome and early adopters are encouraged to try it out. Issues and suggestions should be posted to Documenter.jl's issue tracker.

# Additional makedocs options for HTML output

sitename is the site's title displayed in the title bar and at the top of the navigation menu.

pages defines the hierarchy of the navigation menu.