# Syntax

This section of the manual describes the syntax used by Documenter to build documentation. For supported Markdown syntax, see the documentation for the Markdown standard library in the Julia manual.

## @docs block

Splice one or more docstrings into a document in place of the code block, i.e.

@docs
Documenter
makedocs
deploydocs


This block type is evaluated within the CurrentModule module if defined, otherwise within Main, and so each object listed in the block should be visible from that module. Undefined objects will raise warnings during documentation generation and cause the code block to be rendered in the final document unchanged.

Objects may not be listed more than once within the document. When duplicate objects are detected an error will be raised and the build process will be terminated.

To ensure that all docstrings from a module are included in the final document the modules keyword for makedocs can be set to the desired module or modules, i.e.

makedocs(
modules = [Documenter],
)

which will cause any unlisted docstrings to raise warnings when makedocs is called. If modules is not defined then no warnings are printed, even if a document has missing docstrings.

Notice also that you can use @docs to display the documentation strings of only specific methods, by stating the dispatch types. For example

@docs
f(::Type1, ::Type2)


will only display the documentation string of f that is related to these types. This can be useful when your module extends a function and adds a documentation string to that new method.

Note that when specifying signatures, it should match the method definition exactly. Documenter will not match methods based on dispatch rules. For example, assuming you have a docstring attached to foo(::Integer) = ..., then neither foo(::Number) nor foo(::Int64) will match it in an at-docs block (even though Int64 <: Integer <: Number). The only way you can splice that docstring is by listing exactly foo(::Integer) in the at-docs block.

## @autodocs block

Automatically splices all docstrings from the provided modules in place of the code block. This is equivalent to manually adding all the docstrings in a @docs block.

@autodocs
Modules = [Foo, Bar, Bar.Baz]
Order   = [:function, :type]


The above @autodocs block adds all the docstrings found in modules Foo, Bar, and Bar.Baz that refer to functions or types to the document. Note that a submodule must be listed explicitly in order to include the docstrings within it.

Each module is added in order and so all docs from Foo will appear before those of Bar. Possible values for the Order vector are

• :module
• :constant
• :type
• :function
• :macro

If no Order is provided then the order listed above is used.

When a potential docstring is found in one of the listed modules, but does not match any value from Order then it will be omitted from the document. Hence Order acts as a basic filter as well as sorter.

In addition to Order, a Pages vector may be included in @autodocs to filter docstrings based on the source file in which they are defined:

@autodocs
Modules = [Foo]
Pages   = ["a.jl", "b.jl"]


In the above example docstrings from module Foo found in source files that end in a.jl and b.jl are included. The page order provided by Pages is also used to sort the docstrings. Note that page matching is done using the end of the provided strings and so a.jl will be matched by any source file that ends in a.jl, i.e. src/a.jl or src/foo/a.jl.

To filter out certain docstrings by your own criteria, you can provide a function with the Filter keyword:

@autodocs
Modules = [Foo]
Filter = t -> typeof(t) === DataType && t <: Foo.C


In the given example, only the docstrings of the subtypes of Foo.C are shown. Instead of an anonymous function you can give the name of a function you defined beforehand, too:

@autodocs
Modules = [Foo]
Filter =  myCustomFilterFunction


To include only the exported names from the modules listed in Modules use Private = false. In a similar way Public = false can be used to only show the unexported names. By default both of these are set to true so that all names will be shown.

Functions exported from Foo:

@autodocs
Modules = [Foo]
Private = false
Order = [:function]


Private types in module Foo:

@autodocs
Modules = [Foo]
Public = false
Order = [:type]

Note

When more complex sorting is needed then use @docs to define it explicitly.

Used in markdown links as the URL to tell Documenter to generate a cross-reference automatically. The text part of the link can be a docstring, header name, or GitHub PR/Issue number.

# Syntax

... [makedocs](@ref) ...

# Functions

@docs
makedocs


... [Syntax](@ref) ...

... [#42](@ref) ...

Plain text in the "text" part of a link will either cross-reference a header, or, when it is a number preceded by a #, a GitHub issue/pull request. Text wrapped in backticks will cross-reference a docstring from a @docs block.

@refs may refer to docstrings or headers on different pages as well as the current page using the same syntax.

Note that depending on what the CurrentModule is set to, a docstring @ref may need to be prefixed by the module which defines it.

In some cases a document may contain multiple headers with the same name, but on different pages or of different levels. To allow @ref to cross-reference a duplicate header it must be given a name as in the following example

# [Header](@id my_custom_header_name)

...

... [Custom Header](@ref my_custom_header_name) ...

The link that wraps the named header is removed in the final document. The text for a named @ref ... does not need to match the header that it references. Named @ref ...s may refer to headers on different pages in the same way as unnamed ones do.

Duplicate docstring references do not occur since splicing the same docstring into a document more than once is disallowed.

### Named doc @refs

Docstring @refs can also be "named" in a similar way to headers as shown in the Duplicate Headers section above. For example

module Mod

"""
Both of the following references point to g found in module Main.Other:

* [Main.Other.g](@ref)
* [g](@ref Main.Other.g)

"""
f(args...) = # ...

end

This can be useful to avoid having to write fully qualified names for references that are not imported into the current module, or when the text displayed in the link is used to add additional meaning to the surrounding text, such as

Use [for i = 1:10 ...](@ref for) to loop over all the numbers from 1 to 10.
Note

Named doc @refs should be used sparingly since writing unqualified names may, in some cases, make it difficult to tell which function is being referred to in a particular docstring if there happen to be several modules that provide definitions with the same name.

## @meta block

This block type is used to define metadata key/value pairs that can be used elsewhere in the page. Currently recognised keys:

• CurrentModule: module where Documenter evaluates, for example, @docs-block and @ref-links.
• DocTestSetup: code to be evaluated before a doctest, see the Setup Code section under Doctests.
• DocTestFilters: filters to deal with, for example, unpredictable output from doctests, see the Filtering Doctests section under Doctests.
• EditURL: link to where the page can be edited. This defaults to the .md page itself, but if the source is something else (for example if the .md page is generated as part of the doc build) this can be set, either as a local link, or an absolute url.
• Draft: boolean for overriding the global draft mode for the page.

Example:

@meta
CurrentModule = FooBar
DocTestSetup  = quote
using MyPackage
end
DocTestFilters = [r"Stacktrace:[\s\S]+"]


Note that @meta blocks are always evaluated in Main.

## @index block

Generates a list of links to docstrings that have been spliced into a document. Valid settings are Pages, Modules, and Order. For example:

@index
Pages   = ["foo.md"]
Modules = [Foo, Bar]
Order   = [:function, :type]


When Pages or Modules are not provided then all pages or modules are included. Order defaults to

[:module, :constant, :type, :function, :macro]

if not specified. Order and Modules behave the same way as in @autodocs blocks and filter out docstrings that do not match one of the modules or categories specified.

Note that the values assigned to Pages, Modules, and Order may be any valid Julia code and thus can be something more complex than an array literal if required, i.e.

@index
Pages = map(file -> joinpath("man", file), readdir("man"))


It should be noted though that in this case Pages may not be sorted in the order that is expected by the user. Try to stick to array literals as much as possible.

## @contents block

Generates a nested list of links to document sections. Valid settings are Pages and Depth.

@contents
Pages = ["foo.md"]
Depth = 5


As with @index if Pages is not provided then all pages are included. The default Depth value is 2, i.e. header levels 1 and 2 are included. Depth also accepts UnitRanges, to make it possible to configure also the minimum header level to be shown. Depth = 2:3 can be used to include only headers with levels 2-3, for example.

## @example block

Evaluates the code block and inserts the result of the last expression into the final document along with the original source code. If the last expression returns nothing, the stdout and stderr streams of the whole block are inserted instead. A semicolon ; at the end of the last line has no effect.

@example
a = 1
b = 2
a + b


The above @example block will splice the following into the final document

julia
a = 1
b = 2
a + b



3


Leading and trailing newlines are removed from the rendered code blocks. Trailing whitespace on each line is also removed.

Note

The working directory, pwd, is set to the directory in build where the file will be written to, and the paths in include calls are interpreted to be relative to pwd. This can be customized with the workdir keyword of makedocs.

Hiding Source Code

Code blocks may have some content that does not need to be displayed in the final document. # hide comments can be appended to lines that should not be rendered, i.e.

@example
import Random # hide
Random.seed!(1) # hide
A = rand(3, 3)
b = [1, 2, 3]
A \ b


Note that appending # hide to every line in an @example block will result in the block being hidden in the rendered document. The results block will still be rendered though. @setup blocks are a convenient shorthand for hiding an entire block, including the output.

Empty Outputs

When an @example block returns nothing, the results block will show instead the stdout and stderr streams produced by the whole block. If these are empty, the results block is not displayed at all; only the source code block will be shown in the rendered document.

Named @example Blocks

By default @example blocks are run in their own anonymous Modules to avoid side-effects between blocks. To share the same module between different blocks on a page the @example can be named with the following syntax

@example 1
a = 1


@example 1
println(a)


The name can be any text, not just integers as in the example above, i.e. @example foo.

Named @example blocks can be useful when generating documentation that requires intermediate explanation or multimedia such as plots as illustrated in the following example

First we define some functions

@example 1
using PyPlot # hide
f(x) = sin(2x) + 1
g(x) = cos(x) - x


and then we plot f over the interval from -π to π

@example 1
x = range(-π, π; length=50)
plot(x, f.(x), color = "red")
savefig("f-plot.svg"); nothing # hide


![](f-plot.svg)

and then we do the same with g

@example 1
plot(x, g.(x), color = "blue")
savefig("g-plot.svg"); nothing # hide


![](g-plot.svg)

Note that @example blocks are evaluated within the directory of build where the file will be rendered . This means that in the above example savefig will output the .svg files into that directory. This allows the images to be easily referenced without needing to worry about relative paths.

Info

If you use Plots.jl with the default backend GR.jl, you will likely see warnings like

qt.qpa.xcb: could not connect to display
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.

To fix these, you need to set the environment variable GKSwstype to 100. For example, if you use GitHub actions to build your documentation, you can modify the default script to

- name: Build and deploy
env:
GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }} # For authentication with GitHub Actions token DOCUMENTER_KEY:${{ secrets.DOCUMENTER_KEY }} # For authentication with SSH deploy key
GKSwstype: "100" # https://discourse.julialang.org/t/generation-of-documentation-fails-qt-qpa-xcb-could-not-connect-to-display/60988
run: julia --project=docs --color=yes docs/make.jl

Alternatively, you can set this environment variable directly in Julia using

ENV["GKSwstype"] = "100"

@example blocks automatically define ans which, as in the Julia REPL, is bound to the value of the last evaluated expression. This can be useful in situations such as the following one where binding the object returned by plot to a named variable would look out of place in the final rendered documentation:

@example
plot([sin, x -> 2sin(x) + x], -2π, 2π)
draw(SVG("plot.svg", 6inch, 4inch), ans); nothing # hide


![](plot.svg)

Color output

@example blocks support colored text output by mapping ANSI escape codes to HTML. For example, this block:

@example
printstyled("Here are some colors:\n"; color=:red, bold=true)
for color in 0:15
print("\e[38;5;$(color);48;5;$(color)m  ")
color % 8 == 7 && println()
end
print("\e[m")


results in the following input and output blocks:

printstyled("Here are some colors:\n"; color=:red, bold=true)
for color in 0:15
print("\e[38;5;$(color);48;5;$(color)m  ")
color % 8 == 7 && println()
end
print("\e[m")
Here are some colors:
0     1     2     3     4     5     6     7
8     9    10    11    12    13    14    15

Disable color output

To disable color output globally, pass ansicolor=false to Documenter.HTML, and to disable locally for the block, use ansicolor=false, like so:

@example; ansicolor=false
printstyled("hello, world"; color=:red, bold=true)


Delayed Execution of @example Blocks

@example blocks accept a keyword argument continued which can be set to true or false (defaults to false). When continued = true the execution of the code is delayed until the next continued = false @example-block. This is needed for example when the expression in a block is not complete. Example:

@example half-loop; continued = true
for i in 1:3
j = i^2

Some text explaining what we should do with j
@example half-loop
println(j)
end


Here the first block is not complete – the loop is missing the end. Thus, by setting continued = true here we delay the evaluation of the first block, until we reach the second block. A block with continued = true does not have any output.

## @repl block

These are similar to @example blocks, but add a julia> prompt before each toplevel expression and do not fail upon encountering an error. The # hide syntax may be used in @repl blocks in the same way as in @example blocks. Furthermore, a semicolon ; at the end of a line will suppress the output as in the Julia REPL.

@repl
a = 1
b = 2
a + b


will generate

julia
julia> a = 1
1

julia> b = 2
2

julia> a + b
3


And likewise

@repl
sqrt(-1)


will generate

julia
julia> sqrt(-1)
ERROR: DomainError with -1.0:
sqrt will only return a complex result if called with a complex argument. Try sqrt(Complex(x)).


@repl blocks support colored output, just like @example blocks. The following block

@repl
printstyled("hello, world"; color=:red, bold=true)


gives

julia> printstyled("hello, world"; color=:red, bold=true)hello, world
Disable color output

To disable color output globally, pass ansicolor=false to Documenter.HTML, and to disable locally for the block, use ansicolor=false, like so:

@repl; ansicolor=false
printstyled("hello, world"; color=:red, bold=true)


Named @repl <name> blocks behave in the same way as named @example <name> blocks.

Note

The working directory, pwd, is set to the directory in build where the file will be written to, and the paths in include calls are interpreted to be relative to pwd. This can be customized with the workdir keyword of makedocs.

Soft vs hard scope

Julia 1.5 changed the REPL to use the soft scope when handling global variables in for loops etc. When using Documenter with Julia 1.5 or above, Documenter uses the soft scope in @repl-blocks and REPL-type doctests.

## @setup <name> block

These are similar to @example blocks, but both the input and output are hidden from the final document. This can be convenient if there are several lines of setup code that need to be hidden.

Note

Unlike @example and @repl blocks, @setup requires a <name> attribute to associate it with downstream @example <name> and @repl <name> blocks.

@setup abc
using RDatasets
using DataFrames
iris = dataset("datasets", "iris")


@example abc
println(iris)


## @eval block

Evaluates the contents of the block and inserts the resulting value into the final document.

In the following example we use the PyPlot package to generate a plot and display it in the final document.

@eval
using PyPlot

x = range(-π, π; length=50)
y = sin.(x)

plot(x, y, color = "red")
savefig("plot.svg")

nothing


![](plot.svg)

Another example is to generate markdown tables from machine readable data formats such as CSV or JSON.

@eval
using CSV
using Latexify
mdtable(df,latex=false)


Which will generate a markdown version of the CSV file table.csv and render it in the output format.

Note that each @eval block evaluates its contents within a separate module. When evaluating each block the present working directory, pwd, is set to the directory in build where the file will be written to, and the paths in include calls are interpreted to be relative to pwd.

Also, instead of returning nothing in the example above we could have returned a new Markdown.MD object through Markdown.parse. This can be more appropriate when the filename is not known until evaluation of the block itself.

Note

In most cases @example is preferred over @eval. Just like in normal Julia code where eval should only be considered as a last resort, @eval should be treated in the same way.

## @raw <format> block

Allows code to be inserted into the final document verbatim. E.g. to insert custom HTML or LaTeX code into the output.

The format argument is mandatory and Documenter uses it to determine whether a particular block should be copied over to the output or not. Currently supported formats are html and latex, used by the respective writers. A @raw block whose format is not recognized is usually ignored, so it is possible to have a raw block for each output format without the blocks being duplicated in the output.

The following example shows how SVG code with custom styling can be included into documents using the @raw block.

@raw html
<svg style="display: block; margin: 0 auto;" width="5em" heigth="5em">
<circle cx="2.5em" cy="2.5em" r="2em" stroke="black" stroke-width=".1em" fill="red" />
</svg>


It will show up as follows, with code having been copied over verbatim to the HTML file.