Contribute to json language server with a custom language.

[RedCMD]

Allow extensions to enable the builtin json-language-features extension on their own personal json languageId
PR fixes #198025
@aeschli

following the PR of #146731 as reference

Extensions wanting to enable the json language server
only need to add 3 things to their package.json file:

"main": "",
"extensionDependencies": [
	"vscode.json-language-features"
],
"contributes": {
	"jsonLanguageParticipants": [
		{
			"languageId": "foobar"
		}
	]
}

EDIT: A blank "main": "" is required for "extensionDependencies" to be able to start the json-language-features extension

I am unsure how to go about sending a allowComments setting to the language server
maybe allowComments could be part of schema? EDIT: it already is

vscode/extensions/json-language-features/server/src/jsonServer.ts

Line 363 in 6f7e102

const documentSettings: DocumentLanguageSettings = textDocument.languageId === 'jsonc' ? { comments: 'ignore', trailingCommas: 'warning' } : { comments: 'error', trailingCommas: 'error' };

currently I've just hard coded the snippets language in jsonServer.ts#L363 EDIT: removed
and everything relating to comments in languageParticipants.ts#L17-L21 is currently unused

[RedCMD]

@aeschli should I remove the optional allow comments sections?
as I'm not sure how to hook them up with the language server

[aeschli]

It would be nice if we can keep it simple an only support extending json, not also jsonc.

That said, yes, it's already possible to allow comments via scheme, but again, we consider this a VS Code internal thing.

[aeschli]

I don't want to hard code the snippets language...

We need to give the server a list of language ids. It e.g. needs it to dynamically register the formatters. I think that's an oversight in the HTML code.
Along with that list we can also give the 'allowComment`.

[RedCMD]

It e.g. needs it to dynamically register the formatters.

Found it

vscode/extensions/json-language-features/server/src/jsonServer.ts

Line 256 in 6f7e102

const documentSelector = [{ language: 'json' }, { language: 'jsonc' }];

Yeah.. html does hardcode handlebars for its dynamic formatter

vscode/extensions/html-language-features/server/src/htmlServer.ts

Line 255 in 6f7e102

const documentSelector = [{ language: 'html' }, { language: 'handlebars' }];

Tho I still have no idea how to pass the languageParticipants to the server
would you be able to give me a pointer in the right direction?

only support extending json, not also jsonc
we can also give the allowComment

I'm not sure I understand, you don't want to support extending jsonc, but you do want to support allowComment?
Currently I have no difference between json and jsonc other than allowComment

it's already possible to allow comments via scheme
I don't want to hard code the snippets language...

I've double checked that works, so I guess I can safely remove the hardcoded snippets from jsonServer.ts#L363
global-snippets.json#L3

[aeschli]

Thanks, now all looks good. I'll merge it for February.