Your First Extension

Let's start by creating a simple extension to learn the syntax and how to add stuff:

/* the main structure of your extension */

Rarry.registerExtension({
  id: "myFirstExtension", // unique id for your extension

  category: {
    name: "My Extension", // the name shown in the toolbox
  },

  blocks: [
    {
      /* create an output block */
      type: Rarry.BlockType.OUTPUT,
      id: "helloBlock",
      text: "hello",
    },
  ],

  code: {
    /* the code executed by your block */
    helloBlock: () => {
      return "block"; // since it's an output, it needs to return something
    },
  },
});

Rarry.registerExtension() is available globally, so you don't need to import anything. Paste the code into the editor's Custom Extensions popup (or ship it as a built-in extension file) and it will register immediately.

After importing this extension, you will see a new category called "My Extension" appear. That's your extension.

Inside, you will find a "hello" block which returns "block" as specified in the extension's code.

The Extension Descriptor

Rarry.registerExtension() takes a single extension descriptor object. These are the top-level keys:

Key	Type	Description
id	string	Unique identifier for the extension. Required.
category	object	The toolbox category: { name, color, iconURI }.
blocks	array	The block definitions added by this extension.
code	object	Maps each block's id to the function that runs it.
shapes	object	Custom connection shapes, keyed by shape name. See Custom Shapes.
notches	object	Custom statement notch shapes, keyed by connection check type.

You can use plain string values ("output", "value", "menu", ...) or the constants exposed on the global Rarry object (recommended):

• Rarry.BlockType: STATEMENT, CAP, OUTPUT
• Rarry.InputType: VALUE, STATEMENT, MENU
• Rarry.BlockShape: NUMBER, STRING, ARGUMENT, ARRAY, OBJECT, SET