Toying around with Gtk bindings

application.rb

require 'gir_ffi-gtk3'

Gtk.init

app = Gtk::Application.new('org.gtk.example', :flags_none)

app.signal_connect('startup') do
  window = Gtk::ApplicationWindow.new(app)
  
  menu = Gtk::Menu.new
  menu_item = Gtk::MenuItem.new
  menu_item.label = 'test'
  menu.append(menu_item) { puts 'Yes!' }
  
# next line gives me this error:
# (ruby:21453): GLib-GObject-CRITICAL **: g_value_set_instance: assertion `g_value_type_compatible (G_TYPE_FROM_INSTANCE (instance), G_VALUE_TYPE (value))' failed
  app.app_menu = menu
  
  window.show
end

app.run(ARGV)