Provide additional language server support for Elixir

[scottming]

Check for existing issues

• Completed

Language

elixir

Tree Sitter parser link

https://github.com/elixir-lang/tree-sitter-elixir

Language server link

https://github.com/lexical-lsp/lexical

Misc notes

Hello Zed team,

I have tried out Zed and found that it opens quickly and provides a great user experience.

I want to suggest adding an option for custom LS. As a committer of Lexical, I mainly use it for developing Elixir projects. It is speedy and has many unique features, such as Real-time diagnostics support, Context-aware code completion, Consistent and Stable Formatting, etc.

Welcome to check out our README and see our design philosophy.

FYI, for neovim config, I just need to:

local lspconfig = require("lspconfig")
local configs = require("lspconfig.configs")

local M = {
	filetypes = { "elixir", "eelixir", "heex", "surface" },
	cmd = { "/Users/scottming/Code/lexical/_build/dev/rel/lexical/start_lexical.sh" },
	settings = {},
}

function M.load_lexical()
	if not configs.lexical then
		configs.lexical = {
			default_config = {
				filetypes = M.filetypes,
				root_dir = function(fname)
					local project = lspconfig.util.root_pattern(".git")(fname)
					return lspconfig.util.root_pattern("mix.exs", ".git")(fname) or vim.loop.os_homedir()
				end,
			},
		}
	end
end

return M

[mikayla-maki]

Hi y'all,

We don't fully support lexical yet, but in the meantime the latest version in Zed preview (v0.106.2) supports a new settings field which could be used to provide access to the lexical LSP, as long as it communicates over standard in and out. An analoguous setting to the above would be:

{
// Other settings fields
  "elixir": {
    "lsp": {
       "local": {
            "path": "/Users/scottming/Code/lexical/_build/dev/rel/lexical/start_lexical.sh",
            "arguments": [""]
        }
     }
  }
}

Let me know if there's any trouble getting it to work :)

[scottming]

Hello, @mikayla-maki Thanks for the team's work. I tried Zed through the branch of this PR, and I found no issues with diagnostics, format, hover, or goto definition.

However, there are some problems with autocompletion. For example, when entering a module name after an alias, like: alias Le|(| is the cursor), the module cannot be autocompleted correctly. Additionally, autocompletion does not work for submodules after a dot in a module, like Lexical.|

I checked the backend logs and found that the Zed client is not sending the correct request to Lexical. So, this might be a bug in the client. However, I don't know how to view the client's request logs. Can you please guide me on how to do that?