[clangd-dev] RFC: Semantic highlighting

[Jan Korous via clangd-dev]

Hi,

I am starting to work on semantic highlighting in clangd.

There's currently no mention of that in LSP but it seems like this proposal is on the right path to get accepted:
https://github.com/Microsoft/vscode-languageserver-node/pull/367 

TLDR: the proposal introduces new capabilities and server notification.
- New client boolean capability flag.
- New server capability - server shares a lookup table of semantic categories with client in response.
- Semantic categories are defined by TextMate scopes. https://www.sublimetext.com/docs/3/scope_naming.html
- Server sends notifications containing line number, column number, length and semantic category (index in the lookup table).
- Server is responsible for sending only delta information (not full document every time).
- Server is responsible for ignoring trivial shift edits to documents (e. g. newline at the start of the document).

My intention is to implement interface from the proposal.

Does anyone have any thoughts on this?

Thanks.

Jan