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Documentation for the Dart language and tools.

branch: master

Dart Website (

Build Status

The site. Built with Jekyll and hosted on App Engine.

To give us feedback, please file issues with the Dart project.

Contributions welcome! (Just sign our CLA.) Details on processes, formatting, and style are in Writing for You can fork and submit patches at


Contains all the working files.
Contains app engine configuration files.
Documents, HTML files, images, etc. You will work out of here normally.
Generated by Jekyll, to be deployed to server. This directory is transient, can be deleted.

Configuring your system

  • Ensure you have Ruby 1.9.3. (Version 2.0.0p247 worked for me.)
  • Ensure you have Python 2.7.
  • Open a new Terminal.
  • Run sudo gem install fast-stemmer -v '1.0.2'.
  • Run sudo gem install bundler.
  • Run sudo bundle install from the root of your dartlang project.
    • This gives you liquid, jekyll, and more.
  • If you see errors similar to library X (at master) is not checked out. Please run 'bundle install', you should run bundle install (without the sudo).
  • Download and install the App Engine launcher:
    • Tell App Engine to use Python 2.7 if it's not.
      • It will say, in the log "you're using 2.6".
      • On a Mac?
    • Ask an admin to invite you to modify the Dart project on the Google App Engine.

Tips for Windows

  • Install Python and Ruby using Windows installers.
  • Install ruby dev kit for Windows.
  • Run gem install bundler.
  • Run bundle install from the root of your dartlang project.

GitHub setup

  • Create a GitHub login login if you don't already have one.
  • Ask an admin to invite you to the dart-lang project on GitHub.

Contributing via Chromium Code Review

On a Mac:

  • Make sure you have Xcode (contains git)
  • Install depot_tools: $ git clone
  • Add depot_tools to your PATH: $ export PATH="$PATH":pwd/depot_tools NOTE: You may want to add this to your .bashrc file or your shell's equivalent so that you don’t need to reset your $PATH manually each time you open a new shell.


  • Make sure you are in the root of this project.
  • Run the server: make server
  • Your web browser opens to http://localhost:8081.
    • You may need to reload once.
  • Edit, create docs as normal.
  • To run tests, run ./

Windows development tips

You probably won't have make available on the command line by default.

  • To just get up and running, run jekyll from the src/site folder.
  • This starts up the Jekyll webserver and generates into build/static.
  • If Jekyll does not generate output, you need to type chcp 65001 at the command prompt to change the code page to UTF-8. (Jekyll fails silently if this is not done.)
  • To clean, simply delete the contents of build/static and restart jekyll.

Deploying the site

  • Run make clean && make deploy.
    • This builds the site and places everything into build/.
    • This command also uses the current branch for the app engine version name.
    • This command will then deploy the site. (Note: You can also run make clean && make build and then deploy using App Engine.)
  • You will probably need to generate an App-specific password.
    • Save this into the App Engine Launcher during the first deployment.

Regenerating Dartisans playlists

Did you just run a Dartisans? Good for you! Here's what you need to do:

  1. Update the description to be present tense (instead of future), and remove the link to the moderator page.
  2. Ensure the episode is added to the Dartisans playlist, owned by Google Developers channel.
  3. Sort the playlist by date.
  4. Ensure your episode explicitly sets a Recorded On date.
  5. Format your episode's title like this: "Dartisans ep. XX: Subtitle Here"
  6. Pick a great image thumbnail. Don't use the static Dart logo.
  7. Now run make dartisansplaylist
  8. Test it, commit, and go!

Updating the book

The files under docs/dart-up-and-running/contents are autogenerated from the DocBook files for Dart: Up and Running. Here's how to update these files.

First, prepare:

  • Make sure dart (the Dart VM) is in your PATH.

    which dart /Users/me/dart/dart-sdk/bin/dart

  • Make sure xsltproc is in your PATH.

    which xsltproc /usr/bin/xsltproc

  • Find a copy of the latest .xml files that make up dart-up-and-running. For example:

    ls ~/Spot/dartbook/GITHUB LICENSE bookinfo.xml ch02.xml ch05.xml figs ch00.xml ch03.xml code foreword.xml book.xml ch01.xml ch04.xml colo.xml

Now you're ready. From the top directory of this repo, run the following command, specifying the directory that contains ch*.xml:

make book BOOK_XML_DIR=<dir-with-xml-files>


make book BOOK_XML_DIR=~/Spot/dartbook/GITHUB

Wait 4-5 minutes for results.

Very carefully check the diffs, paying special attention to the headers at the top. Rerun the make book command if you aren't sure of the changes.

(Yes, different runs of make book can have different results, even when the .xml files haven't changed. The problem I've noticed has been misnaming files or skipping them in the navigation. Reported as

Running doc-code-verify

doc-code-verify ( is a tool to verify source code samples embedded within the documentation. It checks that all code snippets in the documentation are also in the code source thus ensuring that the documentation is always up to date. Running ./ also runs doc_code_verify.dart.

Each article is treated separately. Hence, the code samples in each article are checked against that article's respective code directory. I figured this was the easiest approach.

Here's an example of how to use doc-code-verify. In the article, it looks like:

<!-- BEGIN(min) -->{% prettify dart %}
 * Returns the lesser of two numbers.
 * Returns NaN if either argument is NaN.
 * The lesser of -0.0 and 0.0 is -0.0.
 * If the arguments are otherwise equal (including int and doubles with the
 * same mathematical value) then it is unspecified which of the two arguments
 * is returned.
 *     return min(100, value);
num min(num a, num b) {/*...*/}
{% endprettify %}<!-- END(min) -->

Notice that I added an HTML comment with <!-- BEGIN(min) --> and <!-- END(min) --> in order to wrap the example.

For Markdown, use a triple dash for the HTML comments.

<!--- BEGIN(then_callback) -->{% prettify dart %}
var url = "";
HttpRequest.getString(url).then((String result) {  //
  print("User count: $result");                    // callback function
});                                                //
{% endprettify %}<!--- END(then_callback) -->

That's safe to do for HTML documents as well. See the feet-wet-streams article for more examples of using doc-code-verify with Markdown.

In the code, it looks like this:

// BEGIN(min)
 * Returns the lesser of two numbers.
 * Returns NaN if either argument is NaN.
 * The lesser of -0.0 and 0.0 is -0.0.
 * If the arguments are otherwise equal (including int and doubles with the
 * same mathematical value) then it is unspecified which of the two arguments
 * is returned.
 *     return min(100, value);
num min(num a, num b) {/*...*/}
// END(min)

Notice I added two comments, // BEGIN(min) and // END(min).

Now, whenever is run, doc-code-verify will check to make sure that the source code in the documentation matches the source code in the code directory.

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