engine extension for julia in quarto

Quarto will introduce engine extensions in 1.9, and this is an experimental port of Quarto's Julia engine to the new architecture.

Install it with

quarto add gordonwoodhull/quarto-julia-engine

You'll need the feature/engine-extension-3 branch of Quarto, until it's merged.

Development

To build the TypeScript engine extension:

quarto call build-ts-extension src/julia-engine.ts

This bundles src/julia-engine.ts into _extensions/julia-engine/julia-engine.js.

Implementation notes

A few system utilities are replaced with small Deno wrappers at the top of src/julia-engine.ts. Deno has a better delay but it's not in Quarto's export map currently; it also uses setTimeout().

There is a new Quarto API for the more significant utilities, such as Jupyter and Markdown functions. Quarto passes the API down in ExecutionEngineDiscovery.init() - this may get called multiple times but it will always pass the same Quarto API object.

The delay in readTransportFile() was not awaited previously, so it wasn't effective. Fixing it required making its caller functions async.

String constants are defined in src/constants.ts.