add custom folding strategy

[daiyam]

Hello,

This PR has been discussed with @aeschli at #53910

• allow folding range provider to have an id

interface FoldingRangeProvider {
     id?: string;
     providerFoldingRanges(...) ...
}

• allow the user to enter that id as a strategy

 "editor.foldingStrategy": "explicit"

[aeschli]

@daiyam Thanks a lot for the PR. Please give me some time to review, I'm buried in some other work, but will get to this right after.

[aeschli]

@daiyam If you plan to work on the PR again, maybe it's better to start a new one. Something is off.

As mentioned, revert the changes to folding.ts, but add the code to select the provider in SyntaxRangeProvider.

[daiyam]

@aeschli Ya, I can filter out the providers inside the SyntaxRangeProvider but I still would need to modifyfolding.ts to pass the option EditorOption.foldingStrategy. Is that ok?

[daiyam]

@aeschli If the changes are ok, I will make another PR. Thx

[goyalyashpal]

hi @aeschli , pinging for updates 😇

[aeschli]

An alternative way would be to go the same way we went for formatting:
The setting editor.defaultFormatter allows to select the formatter to use. The name of the formatter is the name of the extension that provides the formatter.

• the setting also supports language specific settings: "[html]": { "editor.defaultFormatter": "esbenp.prettier-vscode" }
• potentially an extension can provide multiple formatters, but this uncommon. We'd just call all of them.
• this change doesn't require any changes to the contribution (no id needed)
• for folding we would use editor.foldingStrategy with that approach. This means that an id of an extension is also a allowed value. Maybe it could also be an array of extension ids, but we'd need to understand if there are use cases for that.

Would that work for your use case? I`d prefer that solution give we already use the approach for formatting where it worked well.

[daiyam]

My personal use case is:

• disable the folding defined by the language provider
• use the foldings defined like with Emacs with my extension Explicit Folding

The main issue is that VSCode the foldings defined by the language provider can't be disabled.

There is an additional issue where we can't define the priority of the folding providers.
So I've added delay when registering the folding provider of my extension so it can get a higher priority.
But by doing so, VSCode won't remember collapsed regions of a file because it won't know the provider due to the delay...

I have a newer version of the PR where the users can finely tune which folding providers to use (doc)

[aeschli]

@daiyam Can you confirm that the proposal as described in #54200 (comment) will help you? Users could set your folding provider as the default. Your provider can offer additional options such as 'explicit and indentation' etc. It would mean that you reimplement the indentation strategy, but IMO that's acceptable.

[daiyam]

@aeschli Yes, your proposal would work.

For explicit and indentation, I've already implemented it: https://github.com/zokugun/vscode-explicit-folding/blob/master/docs/rules/indentation.md

[daiyam]

@aeschli Do you want me to make a new PR with your proposal?

[aeschli]

@daiyam Yes that would be great!

[daiyam]

@aeschli I've made the PR #157434 following your proposal.