This extension embeds WebAssembly powered code blocks and exercises for both the R and Python languages into Quarto documents using HTML-based output formats. The webR and Pyodide WebAssembly engines are used to dynamically execute code in the user's web browser, so only a static web service (such as GitHub Pages, Quarto Pub, or Netlify) is required.

The quarto-live extension focuses on providing:

Interactive R and Python code blocks.
Exercises with optional hints, solutions, and custom grading algorithms.
Rich client-side output such as interactive plots, images, and HTML widgets.
A customisable CodeMirror-based editor with automatic theming, syntax highlighting, autocomplete, code persistence, and autorun capabilities.
Integration with Quarto's OJS engine so that quarto-live code cells update reactively with {ojs} cells.

Installation

To use the quarto-live extension in your own documents, run the following command in a terminal with a Quarto project as the working directory:

quarto add r-wasm/quarto-live

Once installed, the extension can be used with Quarto documents within this project.

Basic Setup

Set the live custom format in your Quarto document's YAML header. For slides, use format: live-revealjs.

---
format: live-html
---

The default rendering engine used by Quarto is jupyter, requiring a Python installation. If you’d prefer to avoid Python you can also explicitly select the knitr engine in the document’s YAML header:

---
format: live-html
engine: knitr
---

Next, after the YAML header but before your content, include setup code for the knitr engine using a relative path:

---
format: live-html
engine: knitr
---
{{< include ./_extensions/r-wasm/live/_knitr.qmd >}}

NOTE: Including _knitr.qmd is not strictly required if you are using the jupyter rendering engine. It is a temporary requirement for the knitr engine and will be removed in a future release of quarto-live.

Usage

Add an interactive code block into your document using the {webr} (for R code) or {pyodide} (for Python code) code block types:

---
title: A Quarto Live Document
engine: knitr
format: live-html
---
{{< include ./_extensions/r-wasm/live/_knitr.qmd >}}
```{webr}
fit = lm(mpg ~ am, data = mtcars)
summary(fit)
plot(fit)
```

Documentation

Further documentation of how to use quarto-live in your documents to create rich interactive content can be found at:

https://r-wasm.github.io/quarto-live/

Development build

To rebuild the Quarto Live runtime, first enter the live-runtime directory and setup your Node environment by installing the required packages with npm:

$ cd live-runtime
$ npm ci

Then, make the required changes to the TypeScript source files and run npm run build to rebuild the runtime:

$ npm run build
> live-runtime@0.1.2-dev build
> npx tsx build.ts
  ../_extensions/live/resources/live-runtime.js    581.1kb
  ../_extensions/live/resources/pyodide-worker.js   22.4kb
  ../_extensions/live/resources/live-runtime.css    18.0kb
⚡ Done in 44ms

Finally, re-render the docs directory to view your changes:

$ cd ../docs
$ quarto preview

Watching for changes during development

A long running build process can be spawned that will watch for changes in the live-runtime directory and automatically rebuild on changes:

$ cd live-runtime
$ npm run watch

Note that a second terminal running quarto preview must also be spawned so that Quarto files are re-rendered when the runtime changes, and in some cases forcing a Quarto re-render will be required by making a small change to a .qmd file in the docs directory.