feat: migrate to vim.lsp.config #3659

Problem:
Nvim 0.11 has vim.lsp.config, which mostly replaces the legacy
nvim-lspconfig "framework".

Solution:
Migrate all configs to `lsp/*` variants. The old configs in
`lua/lspconfig/` are "frozen".

The new configs include these changes:
- `commands` field became raw calls to
  `vim.api.nvim_buf_create_user_command` inside `on_attach`.
- `root_dir` became:
  - `root_markers` whenever the file list was simple didn't need to mach `*`
  - if the logic was complicated, or needed to match something like
    '\*.c', it was defined as a vim.lsp.Config `root_dir` callback.
- `on_config_change` became `before_init`. I don't actually know if this
  is the correct approach, but looking around the documentation of
  `nvim-lspconfig` a saw that it was defined as the function that gets
  called as soon as the config have `root_dir`, and so I thought
  `before_init` might be the closest alternative.
- `docs.description` became a luadoc `@brief` docstring.
- `single_file_support = false`?

Co-authored-by: Aliou Diallo <aliou@users.noreply.github.com>
Co-authored-by: Justin M. Keyes <justinkz@gmail.com>

1 files changed, 41 insertions, 0 deletions

diff --git a/lsp/lean3ls.lua b/lsp/lean3ls.lua
new file mode 100644
index 00000000..58301588
--- /dev/null
+++ b/lsp/lean3ls.lua
@@ -0,0 +1,41 @@
+local util = require 'lspconfig.util'
+
+---@brief
+---
+---https://github.com/leanprover/lean-client-js/tree/master/lean-language-server
+--
+-- Lean installation instructions can be found
+-- [here](https://leanprover-community.github.io/get_started.html#regular-install).
+--
+-- Once Lean is installed, you can install the Lean 3 language server by running
+-- ```sh
+-- npm install -g lean-language-server
+-- ```
+--
+-- Note: that if you're using [lean.nvim](https://github.com/Julian/lean.nvim),
+-- that plugin fully handles the setup of the Lean language server,
+-- and you shouldn't set up `lean3ls` both with it and `lspconfig`.
+return {
+  cmd = { 'lean-language-server', '--stdio', '--', '-M', '4096', '-T', '100000' },
+  filetypes = { 'lean3' },
+  offset_encoding = 'utf-32',
+  root_dir = function(bufnr, on_dir)
+    local fname = vim.api.nvim_buf_get_name(bufnr)
+    fname = vim.fs.normalize(fname)
+    -- check if inside elan stdlib
+    local stdlib_dir
+    do
+      local _, endpos = fname:find '/lean/library'
+      if endpos then
+        stdlib_dir = fname:sub(1, endpos)
+      end
+    end
+
+    on_dir(
+      util.root_pattern 'leanpkg.toml'(fname)
+        or util.root_pattern 'leanpkg.path'(fname)
+        or stdlib_dir
+        or vim.fs.dirname(vim.fs.find('.git', { path = fname, upward = true })[1])
+    )
+  end,
+}