Move lsp config to local file structure

.config/nvim/lsp/ocamllsp.lua

@@ -0,0 +1,88 @@
+---@brief
+---
+--- https://github.com/ocaml/ocaml-lsp
+---
+--- `ocaml-lsp` can be installed as described in [installation guide](https://github.com/ocaml/ocaml-lsp#installation).
+---
+--- To install the lsp server in a particular opam switch:
+--- ```sh
+--- opam install ocaml-lsp-server
+--- ```
+
+-- https://github.com/ocaml/ocaml-lsp/blob/master/ocaml-lsp-server/docs/ocamllsp/switchImplIntf-spec.md
+local function switch_impl_intf(bufnr, client)
+  local method_name = 'ocamllsp/switchImplIntf'
+  ---@diagnostic disable-next-line:param-type-mismatch
+  if not client or not client:supports_method(method_name) then
+    return vim.notify(('method %s is not supported by any servers active on the current buffer'):format(method_name))
+  end
+  local uri = vim.lsp.util.make_given_range_params(nil, nil, bufnr, client.offset_encoding).textDocument.uri
+  if not uri then
+    return vim.notify('could not get URI for current buffer')
+  end
+  local params = { uri }
+  ---@diagnostic disable-next-line:param-type-mismatch
+  client:request(method_name, params, function(err, result)
+    if err then
+      error(tostring(err))
+    end
+    if not result or #result == 0 then
+      vim.notify('corresponding file cannot be determined')
+    elseif #result == 1 then
+      vim.cmd.edit(vim.uri_to_fname(result[1]))
+    else
+      vim.ui.select(
+        result,
+        { prompt = 'Select an implementation/interface:', format_item = vim.uri_to_fname },
+        function(choice)
+          if choice then
+            vim.cmd.edit(vim.uri_to_fname(choice))
+          end
+        end
+      )
+    end
+  end, bufnr)
+end
+
+local language_id_of = {
+  menhir = 'ocaml.menhir',
+  ocaml = 'ocaml',
+  ocamlinterface = 'ocaml.interface',
+  ocamllex = 'ocaml.ocamllex',
+  reason = 'reason',
+  dune = 'dune',
+}
+
+local language_id_of_ext = {
+  mll = language_id_of.ocamllex,
+  mly = language_id_of.menhir,
+  mli = language_id_of.ocamlinterface,
+}
+
+local get_language_id = function(bufnr, ftype)
+  if ftype == 'ocaml' then
+    local path = vim.api.nvim_buf_get_name(bufnr)
+    local ext = vim.fn.fnamemodify(path, ':e')
+    return language_id_of_ext[ext] or language_id_of.ocaml
+  else
+    return language_id_of[ftype]
+  end
+end
+
+local root_markers1 = { 'dune-project', 'dune-workspace' }
+local root_markers2 = { '*.opam', 'opam', 'esy.json', 'package.json' }
+local root_markers3 = { '.git' }
+
+---@type vim.lsp.Config
+return {
+  cmd = { 'ocamllsp' },
+  filetypes = { 'ocaml', 'menhir', 'ocamlinterface', 'ocamllex', 'reason', 'dune' },
+  root_markers = vim.fn.has('nvim-0.11.3') == 1 and { root_markers1, root_markers2, root_markers3 }
+    or vim.list_extend(vim.list_extend(root_markers1, root_markers2), root_markers3),
+  get_language_id = get_language_id,
+  on_attach = function(client, bufnr)
+    vim.api.nvim_buf_create_user_command(bufnr, 'LspOcamllspSwitchImplIntf', function()
+      switch_impl_intf(bufnr, client)
+    end, { desc = 'Switch between implementation/interface' })
+  end,
+}