[RFC] Lua-to-Ex bridge library

This is my first foray in Lua. I wasn’t satisfied with the ergonomics of some of the built-in Lua bridge APIs (e.g. vim.cmd, vim.api.nvim_set_keymap), so I tried to create something a little nicer. Looking for any feedback now that I have something basic working.

Call Ex Commands From Lua

The bex.cmd module lets you invoke Ex commands as functions, with sophisticated conversion of parameters into the formatted command. For example, bex.cmd.autocmd supports arbitrary Lua callables as the action:

local cmd = require('bex.cmd')
cmd.autocmd('CursorHold', '*', function() print("CursorHold fired!") end)

See the bex.cmd module for details on how to override parameter handling for arbitrary Ex commands. Overrides are provided for several common built-in commands.

The bridge back into Lua functions is provided by the bex.bridge module, which you may find helpful in your own Lua code.

Lua-friendly Keymap Setting

Although the bex.cmd module lets you use ordinary Ex command like nnoremap to set keymaps, bex.keymap provides a more Lua-friendly alternative:

-- Print "Hello, world!" when pressing key sequence in
-- normal or visual mode in the current buffer
keymap = require('bex.keymap')
keymap.set {
    buffer = true,
    ["nx <Leader>zzz"] = function() print("Hello, world!") end