Creating a library

This page describes how to create a library in Pen. It consists of the following steps:

  1. Create a library package.
  2. Publish the package.

Creating a library package

Library packages are packages imported and used by other packages. To create it, you run a pen create --library command with your library's name (e.g. foo) in your terminal.

pen create --library foo

Then, you should see a foo directory in your current directory. When you go there, you should see a Foo.pen source file and a pen.json file for package configuration.


Add = \(x number, y number) number {
  x + y


  "type": "library",
  "dependencies": {}

In this example, the Foo.pen file contains an Add function that adds two numbers. And the pen.json configuration file defines a package type of library and its dependencies of none.

Publishing a package

The easiest way to publish your library package is to push the package as a Git repository onto one of Git repository hosting services, such as GitHub.

git add .
git commit
git remote add origin ssh://
git push

Now, your package is ready for use by other packages!

Next steps