open code tag up for extension

[srenatus]

Hello 👋

Thanks for Framework, it's been a pleasure to adopt ✨ and I'm planning to keep working with it.

I've been toying with adding Squint as an accepted language (ClojureScript transpiled to JS). My experiment's branch is here, the change is rather light; but it's also roughed in at this point, with some cut corners.

It would be pretty neat if one was able to mix-and-match JS and CLJS in Framework, like

```cljs echo
(defn squint [x]
    (> (:frequency x) 0.06))
```

```js echo
Plot.rectY(alphabet, {
  x: "letter",
  y: "frequency",
  fill: squint,
}).plot()
```

Now, I don't expect Framework to support Squint (although it would be pretty cool). What would be nice, however, would be to open the tags up to customization of some sort. Squint would just be a first example, I could imagine other cool projects getting unlocked by this 💭

I'd be happy to contribute, but I'd need guidance on how to cleanly allow such extensibility in JS.

What do you think?

[Fil]

Interesting idea! (Note: I took the liberty to edit your message to make the fence code apparent.)

[mbostock]

We could allow the project config to register additional code transforms for getLiveSource?

framework/src/markdown.ts

Lines 52 to 66 in 97aa3ce

	function getLiveSource(content: string, tag: string): string | undefined {
	return tag === "js"
	? content
	: tag === "tex"
	? transpileTag(content, "tex.block", true)
	: tag === "html"
	? transpileTag(content, "html.fragment", true)
	: tag === "svg"
	? transpileTag(content, "svg.fragment", true)
	: tag === "dot"
	? transpileTag(content, "dot", false)
	: tag === "mermaid"
	? transpileTag(content, "await mermaid", false)
	: undefined;
	}

[srenatus]

We could allow the project config to register additional code transforms for getLiveSource?

I think that would be sufficient. Do you want me to just give it a shot? (Is there any precedent in the framework sources, where something additional can be registered?)

[srenatus]

Given SQL tags have landed (🎉), PRQL tags could also be nice and done with this.

[mbostock]

@srenatus Tracking PRQL separately with #1075; some progress in #1078.