Neovim: "native" Lua callbacks in mappings

util.lua

local M = {}
M._cbs = {}

--- Saves a Lua function as a callback and returns a string that can be used to
--- run that function.
---
---@param fn Callback
---@return string
function M.lua_callback(fn)
	assert(type(fn) == 'function', tb('fn must be a function'))
	local callback_number = #M._cbs + 1
	M._cbs[callback_number] = fn
	return ("require'my.utils'._cbs[%d]()"):format(callback_number)
end

--- Saves a Lua function as a callback and returns a string that can be used to
--- run that function from Vim.
---
---@param fn Callback
---@return string
function M.lua_callback_cmd(fn)
  return "lua "..M.lua_callback(fn)
end

--- Wrapper around vim.api.nvim_set_map() that can take native Lua functions.
function M.map(mode, lhs, rhs, opts)
	if type(rhs) == 'function' then
		rhs = '<cmd>' .. M.lua_callback_cmd(rhs) .. '<cr>'
	end
	return api.set_keymap(mode, lhs, rhs, opts)
end

--- Wrapper around vim.api.nvim_buf_set_map() that can take native Lua functions.
function M.bmap(buffer, mode, lhs, rhs, opts)
	if type(rhs) == 'function' then
		rhs = '<cmd>' .. M.lua_callback_cmd(rhs) .. '<cr>'
	end
	api.buf_set_keymap(buffer, mode, lhs, rhs, opts)
end

return M