Reset styling for embedded languages in grammars?

[mjbvz]

Problem

For grammars with embedded languages, the outside scope's colorization can leak into the embedded language:

The above example shows embedding the html grammar in a js template string. Notice that text is orange. No specific html grammar scope applies to it so it picks up the foreground color of string.template.js

Instead, in most cases I feel it would make more sense that text be colored the same at it would be in a normal html file, which in this case would be the default foreground color of the theme

Possible Approach

I've already fixed this issue for ${expressions} in normal js template strings. Manually handling each language and embedded language combination will not scale however.

One idea is to make themes treat the meta.embedded scope as a styling reset point. Themes would just use the same style for meta.embedded as for the default:

	"tokenColors": [
		{
			"settings": {
				"foreground": "#D4D4D4",
				"background": "#1E1E1E"
			}
		},
		{
			"scope": "meta.embedded",
			"settings": {
				"foreground": "#D4D4D4",
				"background": "#1E1E1E"
			}
		},
      ...

This works in my initial testing but may have unintended side effects. It also requires updating every theme

[mjbvz]

@Tyriar or @aeschli, any thoughts on this?

[Tyriar]

You essentially want to clear the scopes for the embedded language block right?

@alexandrudima is quite familiar with the textmate scopes.

[mjbvz]

Yes, I looked through some textmate grammars but didn't see any examples of this

[aeschli]

I'd argue that having red as default isn't wrong, it's still a string, after all. But themes are already free to define such rules such as setting the default background color for 'source' or 'meta.embedded'

I'm against any tricks and customizations of our textmate coloring engine, we should stay compatible. But if you want to add something to our default rules, no problem.

[alexdima]

👍

I'm against any tricks and customizations of our textmate coloring engine, we should stay compatible. But if you want to add something to our default rules, no problem.

[mjbvz]

Ok, sounds like proposed theme changes is the way to go. I'll look into trying this next iteration