Skip to content
Switch branches/tags

Name already in use

A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?
Go to file
Cannot retrieve contributors at this time


This is the of our project. Great to have you here. Here are a few ways you can help make this project better!

Team members

The list of people who have contributed to Skulpt is too big and dynamic to be accurate in a document like this. Luckily Github does an excellent job of keeping track of people who have contributed

Brad Miller is the current owner of the project. But see below for the full list of people with commit privileges.

Learn & listen

This section includes ways to get started with your open source project. Include links to documentation and to different communication channels:

Adding new features

This section includes advice on how to build new features for the project & what kind of process it includes.

  • First you should make a Fork. If you have never made a fork before please read this github help article
  • Check out the document HACKING.rst Although its a work in progress, it contains valuable information about Skulpt and how it is structured, some of the naming conventions, and information to help you understand how it all works.
  • Create a feature branch using this command git checkout -b feature_branch_name
  • Once you have added a new feature make sure you develop some test cases and add them to the test bank. Even better would be to write the failing test first. You can add a test by copying the unit-test template file ./test/ to ./test/unit and give it a descriptive name. Make sure the functions in your test class start with test. Here is some documentation on the unittest module (not everything is implemented in skulpt).
  • Before submitting a pull request please make sure you run ./skulpt test and ./skulpt dist this checks that there are no regressions.
    We have an automatic system to do regression testing, but if your pull request fails it is certain that it will not be accepted.
  • Now you can push this branch to your fork on github (you can do this earlier too) with this command git push -u origin feature_branch_name. And create a Pull Request on github.
  • If the master branch gets updated before your pull request gets pulled in. You can do a rebase to base your commits off the new master. With a command that looks like git rebase upstream/master. Make sure you do a force push to your branch git push --force because you've rewritten history, and all your commits will appear in two fold if you don't

We try to get to pull requests in a very timely way so they don't languish. Nothing is more frustrating than a project that just leaves pull requests sitting there for ages. Usually we get to them in a one or two days.

In short: TL;DR

  • fork: (on github)
  • branch: git checkout -b feature_branch_name
  • add unit-test
  • commit: git commit -m 'failing test' (you can do this more often)
  • write code
  • test: npm run devbuild, npm test, npm run test3, and npm run dist
  • commit: git commit -m 'implement fix' (you can do this more often)
  • push: git push -u origin feature_branch_name
  • pull-request: (on github)

NPM Commands

  • npm run help

    Help on all npm commands.

  • npm run build

    Production, optimized build.

  • npm run devbuild

    Development, unoptimized build

  • npm run watch

    Development, unoptimized build, which will automatically be rebuilt when there are any source changes.

  • npm run dist

    Prepare the distribution: build the optimized Skulpt, run all tests, build docs.

  • npm run brun <pyfile>

    Run Python in the browser. This will automatically rebuild the unoptimized Skulpt first.

  • npm run btest

    Run the unit tests in the browser.

  • npm run repl

    Open the REPL. You need to build Skulpt (either npm run build or npm run devbuild) first.

  • npm test

    Run all tests. You need to build Skulpt (either npm run build or npm run devbuild) first.

  • npm start <py2|py3> <pyfile>

    Run pyfile using either Python 2 (py2) or Python 3 (py3). You need to build Skulpt (either npm run build or npm run devbuild) first.

  • npm run profile <py2|py3> <pyfile>

    Run pyfile using either Python 2 (py2) or Python 3 (py3) with the profiler on. Will report the profiling results to the console. You need to build the optimized Skulpt (npm run build) first.

Coding Style and Conventions

Here are some coding conventions to keep in mind:

  • Sk.ffi.remapToJs and Sk.ffi.remapToPy are your friends. They take care of the details of going from a Python type to a Javascript type and vice versa. They are smart enough to work with common types and even work well recursively converting containers. Sk.ffi.remapToJs is definitely preferred over foo.v
  • Use the pyCheckArgs function at the beginning of anything that will be exposed to a Python programmer.
  • Check the types of arguments when you know what they must be.
  • Explicitly return Sk.builtin.none.none$ for functions and methds that should return None
  • If you are adding a module or package to the library, respect the package/module conventions.
    • modules should be named foo.js or
    • packages should be a directory with an __init__.js or file, and possibly additional modules.

In summer of 2014, we adopted the following style and conventions for our code:

  • Braces: One True Brace style -- that means open braces go on the same line as the if/function/while/for statement, not on the line after.
  • Curly braces everywhere Yes, even if it is only a one line body of an if you should use curly braces to clearly define every block.
  • Use double quotes for strings everywhere.
  • indent: 4 spaces
  • combine your variable declarations at the top. (if you don't agree read this:
  • make it pass jshint as much as possible
    • dangling underscores are ok we use them because we run into a lot of reserved words.
    • don't worry about the 'use strict'; we should add that to the compiler
    • we use a lot of bitwise ops so we can ignore those too
  • Avoid accessing properties with array notation ['{a}'] use dot notation where possible.
  • Don't use jQuery or create other third party library dependencies. If you think you have a really good reason to introduce said dependency then bring it up for discussion. There is also no reason to reinvent the wheel.

There may very well be things I have not covered in this list, but those will be quickly revealed to you by the jshint program.

Our Travis script will run jshint over all the source. You should run jshint as well.
Many editors and IDEs do this automatically for you -- Atom, PyCharm, TextMate has a nice plugin called JSLintMate. You can easily install jshint using the npm package manager that comes with node.


The committers are people who are responsible for reviewing and approving pull requests . These are generally people who have been around the project for a while and have "proven" themselves by contributing good code and ideas to the Skulpt. This list may change over time as people gain or lose interest in Skulpt. If you would like to volunteer contact Brad.

Although a lot of our testing, and checking for adherence to the style guidelines is done automatically the review process I would recommend for committers is as follows:

  1. Look at the diffs for each file on github, if it is pretty obvious what they are doing is correct then that is a good sign.
  2. Look at the tests provided with the PR and try to think if there are additional tests that would provide better coverage. If you think additional tests are needed then you should let the owner of the PR know and have them add more tests. All new PRs that are adding new features should be using the new unittest framework, not the old numbered framework.
  3. Pull the the PR down to your local machine and run all the tests locally. (Unless it is really trivial)
  4. If the code looked a bit more complicated when you examined the diffs, then you should bring it up in your editor and look over the code in context and try to understand it better. If there are issues with how the code is written or if it is unclear about why something was done, then have that conversation with the owner of the PR.
  5. Many of us have our own projects that exercise Skulpt to its limits. If you are particularly concerned about a PR then you may want to try out the built js files in your environment.
  6. It is always appropriate to raise questions and have a group conversation about anything that looks particularly problematic or risky.
  7. With the new style unit tests, You should ask the submitter to file issues for tests that they comment out. This will let us track completeness over time. Not every test needs its own issue. Something like 'when blah feature is added enable tests x,y,z in' should work.

The current group of committers is as follows:


If documentation is your thing, have we got a job for you. There are a few blog posts on how to write modules and work with skulpt but very little of the core is documented beyond the source. Having some good documentation for developers would really help get more people involved.


This section includes ideas on how non-developers can help with the project. Here's a few examples:

  • You can help us answer questions our users have in the google group

  • You can help build and design our website in doc

  • You can help write blog posts about the project

  • Create an example of the project in real world by building something or showing what others have built.

  • Write about other people’s projects based on this project. Show how it’s used in daily life. Take screenshots and make videos!