Support for rust-analyzer's SnippetTextEdits

[augustocdias]

As requested for vim-snip (hrsh7th/vim-vsnip#225), I think it should be nice to be supported in LuaSnip as well...

Reference: https://github.com/rust-analyzer/rust-analyzer/blob/master/docs/dev/lsp-extensions.md#snippet-textedit
Reference: hrsh7th/nvim-cmp#353 (comment)
Reference: simrat39/rust-tools.nvim#74

[L3MON4D3]

What exactly would have to be added to luasnip to enable snippet-textedits?
We have the capability to expand lsp-style snippets at the current cursor position via luasnip.lsp_expand(snippet_body), is that enough?

[augustocdias]

@simrat39 would that be enough to add this to rust-tools?

[simrat39]

umm not really, rust analyzer's snippet text edits are more like normal lsp text edits, they send a location and stuff as well, but I afaik most snippet plugins only support snippet expansion at the current cursor position, so it wouldn't work. It would need a completely separate implementation of TextEdits.

[L3MON4D3]

Expanding at any position shouldn't be a problem, I could add that. I wouldn't implement lsp-communication in luasnip, but that part could be handled by rust-tools?

[augustocdias]

I believe that would be the end goal. Providing the API to call from lsp handlers.

[simrat39]

@L3MON4D3 yes the lsp communication will be handled by rust-tools. We override vim.lsp.utils.apply_text_edit, not ideal but it works so it's whatever, just need the snippet plugin to apply the snippets

[L3MON4D3]

I added functionality to expand lsp-snippets at any position, check here.
Does that work for you?

[L3MON4D3]

Just realized that link doesn't actually get you anywhere, just scroll all the way down and look for lsp_expand

[simrat39]

i'll play around with it, thanks for the support

[simrat39]

This works mostly, but one thing missing is that TextEdits give back a range, which can be used for example replacing multiple lines of text with something else, idk if it's in the scope of this plugin to support that but we would need that.

This is how neovim does it https://github.com/neovim/neovim/blob/master/runtime/lua/vim/lsp/util.lua#L329

[L3MON4D3]

Ah, no I wouldn't like to implement that in Luasnip, srry.

[simrat39]

that's fair, i'll try to see what I can do on rust-tools' side then

[anstadnik]

Hi @simrat39, is there a follow-up to this? I found simrat39/rust-tools.nvim#74 which is closed, does it mean that you won't be able to support the feature?

P.S. I love the amount of quality profile pics in this issue

[L3MON4D3]

Ah, no I wouldn't like to implement that in Luasnip, srry.

I'm going to backtrack on my stance here, it doesn't make sense to require each plugin that wants to utilize luasnip for snippetTextEdits to write their own conversion from snippetTextEdit to luasnip-expand-call.

I'll add an implementation for applying a single snippetTextEdit, would that be enough @simrat39?
(Applying textEdits interleaved with snippetTextEdits seems pretty complicated, is that required?)

[L3MON4D3]

(Taking a closer look, the main problem with applying multiple textEdits is that applying them in any order may cause the lines in the textEdit to no longer correspond to the correct position, but I think I know how to make that work properly)