feat(vimfn): use Lua for more excmds/vimfns

Problem:
Too much boilerplate needed to use Lua to impl an excmd or f_xx
function.

Solution:
- Add `nlua_call_vimfn` which takes the args typval, executes
  Lua, and returns a typval.
- refactor(excmd): lua impl for :log, :lsp

4 files changed, 37 insertions, 27 deletions

diff --git a/runtime/lua/vim/_core/ex_cmd.lua b/runtime/lua/vim/_core/ex_cmd.lua
index a9a7a588ed..3c58dc5ddd 100644
--- a/runtime/lua/vim/_core/ex_cmd.lua
+++ b/runtime/lua/vim/_core/ex_cmd.lua
@@ -2,6 +2,10 @@ local api = vim.api
 local fs = vim.fs
 local util = require('vim._core.util')
 
+--- Parsed ex command arguments for builtin commands, passed from C via `nlua_call_excmd`.
+--- Inherits fields from user command args: args, bang, line1, line2, range, count, reg, smods.
+--- @class vim._core.ExCmdArgs : vim.api.keyset.create_user_command.command_args
+
 local M = {}
 
 --- @param msg string
@@ -151,9 +155,9 @@ local actions = {
 local available_subcmds = vim.tbl_keys(actions)
 
 --- Implements command: `:lsp {subcmd} {name}?`.
---- @param args string
-M.ex_lsp = function(args)
-  local fargs = api.nvim_parse_cmd('lsp ' .. args, {}).args
+--- @param eap vim._core.ExCmdArgs
+M.ex_lsp = function(eap)
+  local fargs = api.nvim_parse_cmd('lsp ' .. eap.args, {}).args
   if not fargs then
     return
   end
@@ -192,11 +196,11 @@ end
 local log_dir = vim.fn.stdpath('log')
 
 --- Implements command: `:log {file}`.
---- @param filename string
---- @param mods string
-M.ex_log = function(filename, mods)
+--- @param eap vim._core.ExCmdArgs
+M.ex_log = function(eap)
+  local filename = eap.args
   if filename == '' then
-    util.wrapped_edit(log_dir, mods)
+    util.wrapped_edit(log_dir, eap.smods)
   else
     local path --- @type string
     -- Special case for NVIM_LOG_FILE
@@ -210,7 +214,7 @@ M.ex_log = function(filename, mods)
       echo_err(("No such log file: '%s'"):format(path))
       return
     end
-    util.wrapped_edit(path, mods)
+    util.wrapped_edit(path, eap.smods)
     vim.cmd.normal { 'G', bang = true }
   end
 end
diff --git a/runtime/lua/vim/_core/server.lua b/runtime/lua/vim/_core/server.lua
index 14f942459d..54d8d104f0 100644
--- a/runtime/lua/vim/_core/server.lua
+++ b/runtime/lua/vim/_core/server.lua
@@ -2,36 +2,40 @@
 
 local M = {}
 
---- Called by builtin serverlist(). Returns all running servers in stdpath("run").
+--- Called by builtin serverlist(). Returns the combined server list (own + peers).
 ---
---- - TODO: track TCP servers, somehow.
---- - TODO: support Windows named pipes.
----
---- @param listed string[] Already listed servers
---- @return string[] # List of servers found on the current machine in stdpath("run").
-function M.serverlist(listed)
+--- @param opts? table Options:
+---              - opts.peer is true, also discover peer servers.
+--- @param addrs string[] Internal ("own") addresses, from `server_address_list`.
+--- @return string[] # Combined list of servers (own + peers).
+function M.serverlist(opts, addrs)
+  if type(opts) ~= 'table' or not opts.peer then
+    return addrs
+  end
+
+  -- Discover peer servers in stdpath("run").
+  -- TODO: track TCP servers, somehow.
+  -- TODO: support Windows named pipes.
   local root = vim.fs.normalize(vim.fn.stdpath('run') .. '/..')
   local socket_paths = vim.fs.find(function(name, _)
     return name:match('nvim.*')
   end, { path = root, type = 'socket', limit = math.huge })
 
-  local found = {} ---@type string[]
   for _, socket in ipairs(socket_paths) do
-    -- Don't list servers twice
-    if not vim.list_contains(listed, socket) then
+    if not vim.list_contains(addrs, socket) then
       local ok, chan = pcall(vim.fn.sockconnect, 'pipe', socket, { rpc = true })
       if ok and chan then
         -- Check that the server is responding
         -- TODO: do we need a timeout or error handling here?
         if vim.fn.rpcrequest(chan, 'nvim_get_chan_info', 0).id then
-          table.insert(found, socket)
+          table.insert(addrs, socket)
         end
         vim.fn.chanclose(chan)
       end
     end
   end
 
-  return found
+  return addrs
 end
 
 return M
diff --git a/runtime/lua/vim/_core/util.lua b/runtime/lua/vim/_core/util.lua
index 973cf1da2d..29ba8c5720 100644
--- a/runtime/lua/vim/_core/util.lua
+++ b/runtime/lua/vim/_core/util.lua
@@ -62,12 +62,14 @@ end
 
 --- :edit, but it respects commands like :hor, :vert, :tab, etc.
 --- @param file string
---- @param mods_str string
-function M.wrapped_edit(file, mods_str)
-  local cmdline = table.concat({ mods_str, 'edit' }, ' ')
-  local mods = vim.api.nvim_parse_cmd(cmdline, {}).mods
-  --- @diagnostic disable-next-line: need-check-nil
-  if mods.tab > 0 or mods.split ~= '' or mods.horizontal or mods.vertical then
+--- @param mods string|vim.api.keyset.cmd_mods Modifier string ("vertical") or structured mods table.
+function M.wrapped_edit(file, mods)
+  assert(mods)
+  if type(mods) == 'string' then
+    mods = vim.api.nvim_parse_cmd(mods .. ' edit', {}).mods --[[@as vim.api.keyset.cmd_mods]]
+  end
+  --- @cast mods vim.api.keyset.cmd_mods
+  if (mods.tab or 0) > 0 or (mods.split or '') ~= '' or mods.horizontal or mods.vertical then
     local buf = M.get_buf_by_name(file)
     if buf == nil then
       buf = vim.api.nvim_create_buf(true, false)
diff --git a/runtime/lua/vim/_meta/api_keysets_extra.lua b/runtime/lua/vim/_meta/api_keysets_extra.lua
index 3b8461892b..7714a27e93 100644
--- a/runtime/lua/vim/_meta/api_keysets_extra.lua
+++ b/runtime/lua/vim/_meta/api_keysets_extra.lua
@@ -111,7 +111,7 @@ error('Cannot require a meta file')
 ---
 --- Command modifiers in a structured format. Has the same structure as the
 --- "mods" key of |nvim_parse_cmd()|.
---- @field smods table
+--- @field smods vim.api.keyset.cmd_mods
 
 --- @class vim.api.keyset.command_info
 --- @field name string