nickel: language support (lsp, tree-siiter)

[colemickens]

Describe your feature request

Hi! Nickel is starting to gain some attention. It would be neat to have support for it in Helix. I haven't looked into this a ton yet, but nickel ships with it's own LSP server, but I opened an issue about a tree-sitter grammar: tweag/nickel#656

I'm not sure if it's possible or makes sense to add support with a tree-sitter grammar?

[the-mikedavis]

Nickel looks pretty cool. They might be able to draw some inspiration from tree-sitter-nix given the similarities in syntax.

Iirc there was some discussion a while back about adding an alternative for syntax highlights that would be simpler to write than a tree-sitter grammar, but in the end I think we prefer to support only tree-sitter since it is possible to build other features on top of it (indents, textobjects, Alt+j/k/h/l motions, eventually folds), and tree-sitter is quite performant compared to some regex-based systems.

[colemickens]

I had a feeling that might be the case and I kind of like it. There's even some discussion on how they're already supporting multiple grammars and I am a big fan of the ecosystem network advantages of investing in LSP/DAP/tree-sitter, etc.

It also seems like someone already hacked on this a bit. Maybe in a few days I can look at this again.

[ErinvanderVeen]

We made https://github.com/nickel-lang/tree-sitter-nickel public.