# Caret

Caret is a world-class math input for the web.

> [!WARNING]  
> **Caret is not ready for public use/contributions.** Caret is not yet usable. Everything can and will change. Do not rely on it. I am not accepting contributions or PRs right now. It is just published so you can poke around if you're curious.
>
> The README information below is written in the present tense, but most of it is not yet true. This document demonstrates my aspirations, not what actually exists!

## Features

- **Parsing.** Caret has built-in support for parsing user input into an easily-consumable tree. This makes it easy to analyze and perform computation on user input.
- **Syntax Highlighting.** Define your own custom syntax highlighting. Create custom rules that use the parsed tree to customize rendering.
- **Live Multiplayer.** Use Caret's built-in CRDT to effortlessly support live multiplayer editing, with or without a central server.

- **Any Frontend Library.** Caret can be integrated with any frontend library or used with plain JavaScript.
- **Custom Rendering.** Provide your own components to customize rendering of all token types.
- **World-Class Accessibility.** Caret has native support for keyboard navigation, screen reader output, speech input, braille displays, and more.

- **LaTeX Input/Output.** Caret can instantly input and output LaTeX for interoperability with other tools.
- **MathQuill Compatibility.** Coming from MathQuill? The MathQuill compatibility layer makes Caret a drop-in replacement.
- **Customize Everything.** Absolutely everything in Caret is modular and customizable. Define your own token types, customizing parsing behavior, and more.

## Alternatives to Caret

Caret is not the only library that allows users to type math on the web. Here are some possible alternatives.

### MathQuill

[MathQuill](http://mathquill.com/) is a robust, battle-tested library for typing math on the web. Desmos uses a [modified version](https://github.com/desmosinc/mathquill) of MathQuill, which also means it is used by the College Board on the SAT.

**Key Points:**

- ✅ User experience is excellent
- ✅ Extremely battle-tested
- ⛔️ Poor developer experience (jQuery-based, bad fit for modern ecosystem)
- ⛔️ Few customization options (not plugin-based, limited to a limited few settings)

### MathLive `<math-field>`

The [MathLive `<math-field>`](https://mathlive.io/mathfield/) is an open-source web component that allows typing math.

On paper, MathLive does many things right. But in practice I find that it has many little papercuts that make it slightly unpleasant as both a user and a developer.

- Reasonable user experience
- Extreme dedication to LaTeX compatibility
- Built-in virtual keyboard
- Wide scope (does many things with lots of configuration options)

### Katex (LaTeX rendering only)

If your only goal is to render static LaTeX math (not allow typing), you should almost certainly use [Katex](https://katex.org/). It's a gold-standard, time-tested tool that does one thing extremely well.

- ✅ Renders to static HTML and CSS on the server or the client
- ✅ Accessible rendering
- ✅ Extremely fast
- ✅ Supports a very large subset of LaTeX
- ✅ Simple, friendly developer experience
- ⛔️ No user input (rendering only)