template for new neovim plugin

new-plugin-setup-template.lua

function M.setup(opts)
  -- Look up keys in user-defined table with fallback to defaults.
  M.opts = setmetatable(opts or {}, {__index = require'app.defaults'})
  M.initialized = true

  -- Insert the engine and register the autocommand if asked to.
  local engine = require'app.engine'
  -- engine.do_work()

  if M.opts.create_app_autocmd then
    engine.create_autocmd()
  end

  -- register App extensions, if any
  if M.opts.extensions ~= nil then
    for _, ext_name in pairs(opts.extensions) do
      local ok, extension = pcall(require, ext_name)
      if not ok then
        -- 4 is error; thanks Neovim… :(
        vim.notify(string.format('extension %s wasn’t correctly loaded', ext_name), 4)
      else
        if extension.register == nil then
          vim.notify(string.format('extension %s lacks the register function', ext_name), 4)
        else
          extension.register(opts)
        end
      end
    end
  end
end