Consider a text editor, which manages a mutable string. Ranges of characters can be assigned particular attributes. Conceptually, every character in the string comes with a key/value map named “attributes”. Some keys are predefined, but apps can define their own custom attributes.

You can ask questions like:

1. What attributes does the 34th Unicode character in the string have?
2. What’s the largest contiguous Range of characters that all have the same attributes as character 34?
3. Is the :italic attribute set for character 34?
4. For what range around character 34 is the :italic attribute set?

I’m writing an app to explore coding in a style inspired by ecological and embodied cognition. Mainly for fun and to keep me off the streets.