jazzy is a command-line utility that generates documentation for Swift or Objective-C
Both Swift and Objective-C projects are supported.
Instead of parsing your source files, jazzy hooks into Clang and
SourceKit to use the AST representation of your code and
its comments for more accurate results. The output matches the look and feel
of Apple’s official reference documentation, post WWDC 2014.
Jazzy can also generate documentation from compiled Swift modules using their symbol graph instead of source code.
This project adheres to the Contributor Covenant Code of Conduct. By participating, you are expected to uphold this code. Please report unacceptable behavior to info@realm.io.
You need development tools to build the project you wish to document. Jazzy supports both Xcode and Swift Package Manager projects.
Jazzy expects to be running on macOS. See below for tips to run Jazzy on Linux.
[sudo] gem install jazzySee Installation Problems for solutions to some common problems.
Run jazzy from your command line. Run jazzy -h for a list of additional options.
If your Swift module is the first thing to build, and it builds fine when running
xcodebuild or swift build without any arguments from the root of your project, then
just running jazzy (without any arguments) from the root of your project should
succeed too!
If Jazzy generates docs for the wrong module then use --module to tell it which
one you'd prefer. If this doesn't help, and you're using Xcode, then try passing
extra arguments to xcodebuild, for example
jazzy --build-tool-arguments -scheme,MyScheme,-target,MyTarget.
If you want to generate docs for several modules at once then see Documenting multiple modules.
You can set options for your project’s documentation in a configuration file,
.jazzy.yaml by default. For a detailed explanation and an exhaustive list of
all available options, run jazzy --help config.
Swift documentation is written in markdown and supports a number of special keywords. Here are some resources with tutorials and examples, starting with the most modern:
- Apple's Writing Symbol Documentation in Your Source Files article.
- Apple's Formatting Your Documentation Content article.
- Apple's Xcode Markup Formatting Reference.
- Erica Sadun's Swift header documentation in Xcode 7 post and her book on Swift Documentation Markup.
For Objective-C documentation the same keywords are supported, but note that the format
is slightly different. In Swift you would write - returns:, but in Objective-C you write @return. See Apple's HeaderDoc User Guide for more details. Note: jazzy currently does not support all Objective-C keywords listed in this document, only @param, @return, @warning, @see, @note, @code, @endcode, and @c.
Jazzy can also generate cross-references within your documentation. A symbol name in backticks generates a link, for example:
- `MyClass` - a link to documentation for
MyClass. - `MyClass.method(param1:)` - a link to documentation for that method.
- `MyClass.method(...)` - shortcut syntax for the same thing.
- `method(...)` - shortcut syntax to link to
methodfrom the documentation of another method or property in the same class. - `[MyClass method1]` - a link to an Objective-C method.
- `-[MyClass method2:param1]` - a link to another Objective-C method.
Jazzy understands Apple's DocC-style links too, for example:
- ``MyClass/method(param1:)`` - a link to the documentation for that method
that appears as just
method(param1:)in the rendered page. - ``<doc:method(_:)-e873>`` - a link to a specific overload of
method(_:). Jazzy can't tell which overload you intend and links to the first one.
If your documentation is for multiple modules then symbol name resolution works approximately as though all the modules have been imported: you can use `TypeName` to refer to a top-level type in any of the modules, or `ModuleName.TypeName` to be specific. If there is an ambiguity then you can use a leading slash to indicate that the first part of the name should be read as a module name: `/ModuleName.TypeName`.
Jazzy can render math equations written in LaTeX embedded in your markdown:
`$equation$`renders the equation in an inline style.`$$equation$$`renders the equation in a display style, centered on a line of its own.
For example, the markdown:
Inline: `$ax^2+bx+c=0$`
Block: `$$x={\frac {-b\pm {\sqrt {b^{2}-4ac}}}{2a}}$$`..renders as:
Math support is provided by KaTeX.
Swift documentation is generated by default.
This is how Realm Swift docs are generated:
jazzy \
--clean \
--author Realm \
--author_url https://realm.io \
--source-host github \
--source-host-url https://github.com/realm/realm-cocoa \
--source-host-files-url https://github.com/realm/realm-cocoa/tree/v0.96.2 \
--module-version 0.96.2 \
--build-tool-arguments -scheme,RealmSwift \
--module RealmSwift \
--root-url https://realm.io/docs/swift/0.96.2/api/ \
--output docs/swift_output \
--theme docs/themesThis is how docs are generated for a project that uses the Swift Package Manager:
jazzy \
--module DeckOfPlayingCards \
--swift-build-tool spm \
--build-tool-arguments -Xswiftc,-swift-version,-Xswiftc,5To generate documentation for a simple Objective-C project, you must pass the following parameters:
--objc--umbrella-header ...--framework-root ...
...and optionally:
--sdk [iphone|watch|appletv][os|simulator]|macosx(default value ofmacosx)--hide-declarations [objc|swift](hides the selected language declarations)
For example, this is how the AFNetworking docs are generated:
jazzy \
--objc \
--author AFNetworking \
--author_url http://afnetworking.com \
--source-host github \
--source-host-url https://github.com/AFNetworking/AFNetworking \
--source-host-files-url https://github.com/AFNetworking/AFNetworking/tree/2.6.2 \
--module-version 2.6.2 \
--umbrella-header AFNetworking/AFNetworking.h \
--framework-root . \
--module AFNetworkingFor a more complicated Objective-C project, instead use --build-tool-arguments
to pass arbitrary compiler flags. For example, this is how Realm Objective-C
docs are generated:
jazzy \
--objc \
--clean \
--author Realm \
--author_url https://realm.io \
--source-host github \
--source-host-url https://github.com/realm/realm-cocoa \
--source-host-files-url https://github.com/realm/realm-cocoa/tree/v2.2.0 \
--module-version 2.2.0 \
--build-tool-arguments --objc,Realm/Realm.h,--,-x,objective-c,-isysroot,$(xcrun --show-sdk-path),-I,$(pwd) \
--module Realm \
--root-url https://realm.io/docs/objc/2.2.0/api/ \
--output docs/objc_output \
--head "$(cat docs/custom_head.html)"See the Objective-C docs for more information and some tips on troubleshooting.
This feature has some rough edges.
To generate documentation for a mixed Swift and Objective-C project you must first generate two SourceKitten files: one for Swift and one for Objective-C.
Then pass these files to Jazzy together using --sourcekitten-sourcefile.
This is how docs are generated from an Xcode project for a module containing both Swift and Objective-C files:
# Generate Swift SourceKitten output
sourcekitten doc -- -workspace MyProject.xcworkspace -scheme MyScheme > swiftDoc.json
# Generate Objective-C SourceKitten output
sourcekitten doc --objc $(pwd)/MyProject/MyProject.h \
-- -x objective-c -isysroot $(xcrun --show-sdk-path --sdk iphonesimulator) \
-I $(pwd) -fmodules > objcDoc.json
# Feed both outputs to Jazzy as a comma-separated list
jazzy --module MyProject --sourcekitten-sourcefile swiftDoc.json,objcDoc.jsonSwift 5.3 added support for symbol graph generation from .swiftmodule files.
Jazzy can use this to generate API documentation. This is faster than using
the source code directly but does have limitations: for example documentation
comments are available only for public declarations, and the presentation of
Swift extensions may not match the way they are written in code.
Some examples:
- Generate docs for the Apple Combine framework for macOS:
The SDK's library directories are included in the search path by default.
jazzy --module Combine --swift-build-tool symbolgraph
- Same but for iOS:
The
jazzy --module Combine --swift-build-tool symbolgraph --sdk iphoneos --build-tool-arguments -target,arm64-apple-ios14.1targetis the LLVM target triple and needs to match the SDK. The default here is the target of the host system that Jazzy is running on, something likex86_64-apple-darwin19.6.0. - Generate docs for a personal
.swiftmodule:This implies thatjazzy --module MyMod --swift-build-tool symbolgraph --build-tool-arguments -I,/Build/Products/Build/Products/MyMod.swiftmoduleexists. Jazzy's--source-directory(default current directory) is searched by default, so you only need the-Ioverride if that's not enough. - For a personal framework:
This implies that
jazzy --module MyMod --swift-build-tool symbolgraph --build-tool-arguments -F,/Build/Products/Build/Products/MyMod.frameworkexists and contains a.swiftmodule. Again the--source-directoryis searched by default if-Fis not passed in. - With pre-generated symbolgraph files:
If you've separately generated symbolgraph files by the use of
jazzy --module MyMod --swift-build-tool symbolgraph --symbolgraph-directory Build/symbolgraphs-emit-symbol-graph, you can pass the location of these files using--symbolgraph-directoryfrom where they can be parsed directly.
See swift symbolgraph-extract -help for all the things you can pass via
--build-tool-arguments: if your module has dependencies then you may need
to add various search path options to let Swift load it.
This feature is new, bugs and feedback welcome
Sometimes it's useful to document multiple modules together in the same site, for example an app and its extensions, or an SDK that happens to be implemented as several modules.
Jazzy can build docs for all these together and create a single site with search, cross-module linking, and navigation.
If all the modules share the same build flags then the easiest way to do this
is with --modules, for example jazzy --modules ModuleA,ModuleB,ModuleC.
If your modules have different build flags then you have to use the config file. For example:
modules:
- module: ModuleA
- module: ModuleB
build_tool_arguments:
- -scheme
- SpecialScheme
- -target
- ModuleB
source_directory: ModuleBProject
- module: ModuleC
objc: true
umbrella_header: ModuleC/ModuleC.h
framework_root: ModuleC
sdk: appletvsimulator
- module: ModuleD
sourcekitten_sourcefile: [ModuleD1.json, ModuleD2.json]This describes a four-module project of which one is 'normal', one requires special Xcode treatment, one is Objective-C, and one has prebuilt SourceKitten JSON.
Per-module options set at the top level are inherited by each module unless
also set locally -- but you can't set both --module and --modules.
Jazzy doesn't support --podspec mode in conjunction with the multiple
modules feature.
The --merge-modules flag controls how declarations from multiple modules
are arranged into categories.
The default of all has Jazzy combine declarations from the modules so there
is one category of classes, one of structures, and so on. To the user this means
they do not worry about which module exports a particular type, although that
information remains available in the type's page.
Setting --merge-modules none changes this so each module is a top-level
category, with the module's symbols listed under it.
Setting --merge-modules extensions is like none except cross-module
extensions are shown as part of their extended type. For example if ModuleA
extends ModuleB.SomeType then those extension members from ModuleA are shown
on the ModuleB.SomeType page along with the rest of SomeType.
You can use --documentation to include guides, custom_categories to customize
the layout with types from whichever modules you want, and --abstract to add
additional markdown content to the per-module category pages.
Use the --title, --readme-title, and --docset-title flags to control the
top-level names of your documentation. Without these, Jazzy uses the name of one
of the modules being documented.
Three themes are provided with jazzy: apple (default), fullwidth and jony.
appleexample: https://realm.io/docs/swift/latest/api/fullwidthexample: https://reduxkit.github.io/ReduxKit/jonyexample: https://harshilshah.github.io/IGListKit/
You can specify which theme to use by passing in the --theme option. You can
also provide your own custom theme by passing in the path to your theme
directory.
| Description | Command |
|---|---|
| Command line option | --documentation={file pattern} |
| Example | --documentation=Docs/*.md |
| jazzy.yaml example | documentation: Docs/*.md |
By default, jazzy looks for one of README.md, README.markdown, README.mdown or README (in that order) in the directory from where it runs to render the index page at the root of the docs output directory.
Using the --documentation option, extra markdown files can be integrated into the generated docs and sidebar navigation.
Any files found matching the file pattern will be parsed and included as a document with the type 'Guide' when generated. If the files are not included using the custom_categories config option, they will be grouped under 'Other Guides' in the sidebar navigation.
There are a few limitations:
- File names must be unique from source files.
- Readme should be specified separately using the
readmeoption.
You can link to a guide from other guides or doc comments using the name of the page
as it appears in the site. For example, to link to the guide generated from a file
called My Guide.md you would write `My Guide`.
| Description | Command |
|---|---|
| Command line option | --abstract={file pattern} |
| Example | --abstract=Docs/Sections/*.md |
| jazzy.yaml example | abstract: Docs/Sections/*.md |
Using the --abstract options, extra markdown can be included after the heading of section overview pages. Think of it as a template include.
The list of files matching the pattern is compared against the list of sections generated and if a match is found, it's contents will be included in that section before listing source output.
Unlike the --documentation option, these files are not included in navigation and if a file does not match a section title, it is not included at all.
This is very helpful when using custom_categories for grouping types and including relevant documentation in those sections.
For an example of a project using both --documentation and --abstract see: https://reswift.github.io/ReSwift/
In Swift mode, Jazzy by default documents only public and open declarations. To
include declarations with a lower access level, set the --min-acl flag to internal,
fileprivate, or private.
By default, Jazzy does not document declarations marked @_spi when --min-acl is
set to public or open. Set the --include-spi-declarations flag to include them.
In Objective-C mode, Jazzy documents all declarations found in the --umbrella-header
header file and any other header files included by it.
You can control exactly which declarations should be documented using --exclude,
--include, or :nodoc:.
The --include and --exclude flags list source files that should be included/excluded
respectively in the documentation. Entries in the list can be absolute pathnames beginning
with / or relative pathnames. Relative pathnames are interpreted relative to the
directory from where you run jazzy or, if the flags are set in the config file, relative
to the directory containing the config file. Entries in the list can match multiple files
using * to match any number of characters including /. For example:
jazzy --include=/Users/fred/project/Sources/Secret.swift-- include a specific filejazzy --exclude=/*/Internal*-- exclude all files with names that begin with Internal and any files under any directory with a name beginning Internal.jazzy --exclude=Impl1/*,Impl2/*-- exclude all files under the directories Impl1 and Impl2 found in the current directory.
Note that the --include option is applied before the --exclude option. For example:
jazzy --include=/*/Internal* --exclude=Impl1/*,Impl2/*-- include all files with names that begin with Internal and any files under any directory with a name beginning Internal, except for those under the directories Impl1 and Impl2 found in the current directory
Declarations with a documentation comment containing :nodoc: are excluded from the
documentation.
Declarations with the @_documentation(visibility:) attribute are treated as though they
are written with the given visibility. You can use this as a replacement for :nodoc: as
part of a transition to Apple's DocC but it is not compatible with Jazzy's symbolgraph mode.
Jazzy arranges documentation into categories. The default categories are things
like Classes and Structures corresponding to programming-language concepts,
as well as Guides if --documentation is set.
You can customize the categories and their contents using custom_categories in
the config file — see the ReSwift docs and
config file
for an example.
Within each category the items are ordered first alphabetically by source
filename, and then by declaration order within the file. You can use
// MARK: comments within the file to create subheadings on the page, for
example to split up properties and methods. There’s no way to customize this
order short of editing either the generated web page or the SourceKitten JSON.
Swift extensions and Objective-C categories allow type members to be declared
across multiple source files. In general, extensions follow the main type
declaration: first extensions from the same source file, then extensions from
other files ordered alphabetically by filename. Swift conditional extensions
(extension A where …) always appear beneath unconditional extensions.
Use this pattern to add or customize the subheading before extension members:
extension MyType {
// MARK: Subheading for this group of methods
…
}When Jazzy is using --swift-build-tool symgraph the source file names and
line numbers may not be available. In this case the ordering is approximately
alphabetical by symbol name and USR; the order is stable for the same input.
Jazzy does not normally create separate web pages for declarations that do not
have any members -- instead they are entirely nested into their parent page. Use
the --separate-global-declarations flag to change this and create pages for
these empty types.
Jazzy normally uses the Swift compiler from the Xcode currently configured by
xcode-select. Use the --swift-version flag or the DEVELOPER_DIR environment
variable to compile with a different Xcode.
The value you pass to --swift-version must be the Swift language version given
by swift --version in the Xcode you want to use. Jazzy uses
xcinvoke to find a suitable Xcode
installation on your system. This can be slow: if you know where Xcode is
installed then it's faster to set DEVELOPER_DIR directly.
For example to use Xcode 14:
jazzy --swift-version 5.7...or:
DEVELOPER_DIR=/Applications/Xcode_14.app/Contents/Developer jazzyAs well as the browsable HTML documentation, Jazzy creates a docset for use with the Dash app.
By default the docset is created at docs/docsets/ModuleName.tgz. Use
--docset-path to create it somewhere else; use --docset-title to change
the docset's title.
Use --docset-playground-url and --docset-icon to further customize the
docset.
If you set both --root-url to be the (https://) URL where you plan to deploy
your documentation and --version to give your documentation a version number
then Jazzy also creates a docset feed XML file and includes an "Install in Dash"
button on the site. This lets users who are browsing your documentation on the
web install and start using the docs in Dash locally.
Jazzy uses SourceKitten to communicate with the Swift build
environment and compiler. The sourcekitten binary included in the Jazzy gem
is built for macOS and so does not run on other operating systems.
To use Jazzy on Linux you first need to install and build sourcekitten
following instructions from SourceKitten's GitHub repository.
Then to generate documentation for a SwiftPM project, instead of running just
jazzy do:
sourcekitten doc --spm > doc.json
jazzy --sourcekitten-sourcefile doc.jsonWe hope to improve this process in the future.
Only extensions are listed in the documentation?
Check the --min-acl setting -- see above.
Unable to find an Xcode with swift version X
- The value passed with
--swift-versionmust exactly match the version number fromswiftc --version. For example Xcode 10.1 needs--swift-version 4.2.1. See the flag documentation. - The Xcode you want to use must be in the Spotlight index. You can check
this using
mdfind 'kMDItemCFBundleIdentifier == com.apple.dt.Xcode'. Some users have reported this issue being fixed by a reboot;mdutil -Emay also help. If none of these work then you can set theDEVELOPER_DIRenvironment variable to point to the Xcode you want before running Jazzy without the--swift-versionflag.
See this document.
Missing docset
Jazzy only builds a docset when you set the --module or --modules flag.
Unable to pass --build-tool-arguments containing commas
If you want Jazzy to run something like xcodebuild -scheme Scheme -destination 'a=x,b=y,c=z'
then you must use the config file instead of the CLI flag because the CLI parser
that Jazzy uses cannot handle arguments that themselves contain commas.
The example config file here would be:
build_tool_arguments:
- "-scheme"
- "Scheme"
- "-destination"
- "a=x,b=y,c=z"Errors running in an Xcode Run Script phase
Running Jazzy from an Xcode build phase can go wrong in cryptic ways when Jazzy
has to run xcodebuild.
Users have reported that error
messages about symbols lacking USRs can be fixed by unsetting
LLVM_TARGET_TRIPLE_SUFFIX as part of the run script.
Warnings about matches and leftovers when using globs and wildcards
Some flags such as --include and --documentation support '*' characters as
wildcards. If you are using the CLI then you must make sure that your shell
does not itself try to interpret them, for example by quoting the token: use
jazzy --documentation '*.md' instead of jazzy --documentation *.md.
Can't find header files / clang
Some of the Ruby gems that Jazzy depends on have native C extensions. This
means you need the Xcode command-line developer tools installed to build
them: run xcode-select --install to install the tools.
/Applications/Xcode: No such file or directory
The path of your active Xcode installation must not contain spaces. So
/Applications/Xcode.app/ is fine, /Applications/Xcode-10.2.app/ is fine,
but /Applications/Xcode 10.2.app/ is not. This restriction applies only
when installing Jazzy, not running it.
Starting with Jazzy 0.10.0, if you see an error similar to dyld: Symbol not found: _$s11SubSequenceSlTl then you need to install the Swift 5 Runtime Support for Command Line Tools.
Alternatively, you can:
- Update to macOS 10.14.4 or later; or
- Install Xcode 10.2 or later at
/Applications/Xcode.app.
Please review jazzy's contributing guidelines when submitting pull requests.
jazzy is composed of two parts:
- The parser, SourceKitten (written in Swift)
- The site generator (written in ruby)
To build and run jazzy from source:
- Install bundler.
- Run
bundle installfrom the root of this repo. - Run jazzy from source by running
bin/jazzy.
Instructions to build SourceKitten from source can be found at SourceKitten's GitHub repository.
- Generate source code docs matching Apple's official reference documentation
- Support for standard Objective-C and Swift documentation comment syntax
- Leverage modern HTML templating (Mustache)
- Leverage the power and accuracy of the Clang AST and SourceKit
- Support for Dash docsets
- Support Swift and Objective-C
This project is released under the MIT license.
Jazzy is maintained and funded by Realm Inc. The names and logos for Realm are trademarks of Realm Inc.
We ❤️ open source software! See our other open source projects, read our blog or say hi on twitter (@realm).