custom_menu.php

<?php
/* Custom Menu Plugin */

// Registration
register_plugin_custom_menu();

function register_plugin_custom_menu() {
  // Plugin ID
  $thisfile = basename(__FILE__, '.php');

  // language
  i18n_merge($thisfile) || i18n_merge($thisfile, 'en_US');

  // requires
  require_once(GSPLUGINPATH . $thisfile . '/php/plugin.class.php');
  require_once(GSPLUGINPATH . $thisfile . '/php/data.class.php');
  require_once(GSPLUGINPATH . $thisfile . '/php/display.class.php');
  require_once(GSPLUGINPATH . $thisfile . '/php/placeholder.class.php');

  // Register plugin
  register_plugin(
    CustomMenu::FILE,
    CustomMenu::i18n_r('PLUGIN_NAME'),
    CustomMenu::VERSION,
    CustomMenu::AUTHOR,
    CustomMenu::URL,
    CustomMenu::i18n_r('PLUGIN_DESC'),
    CustomMenu::PAGE,
    'CustomMenu::admin'
  );

  // Activate actions/filters
  // front-end
    // Placeholder content filter
    add_filter('content', 'CustomMenuPlaceholder::filter');

  // back-end
    // Plugin sidebar
    add_action(CustomMenu::PAGE . '-sidebar', 'createSideMenu' , array(CustomMenu::FILE, CustomMenu::i18n_r('PLUGIN_SIDEBAR'))); // sidebar link
}

// Public functions
// Print a custom menu
function get_custom_menu($name, $classes = array()) {
  $menu = new CustomMenuDisplay($name, $classes);
  $menu->displayMenu();
}