Sunrise if we architect to use a singleton

gistfile1.aw

<?php
/**
 * Here's the Sunrise class demonstrating how it would be used as a singleton.
 * NOTE: Code is for discussion only and has not been tested.
 */
class Sunrise {
  static private $instance = null;

  static public function get_instance() {
    if ( ! isset( self::$instance ) ) {
      self::$instance = new Sunrise();
    }
    return self::$instance;
  }

  private $_delegates = array();

  function __construct() {
    add_action( 'init', array( $this, 'init' ), 0 ); // Do this early
  }

  function register_delegate( $method_name, $callable ) {
    $this->_delegates[$method_name] = $callable;
  }

  function __call( $method_name, $args ) {
    $value = null;

    if ( isset( $this->_delegates[$method_name] ) ) {
      $value = call_user_func_array( $this->_delegates[$method_name], $args );
    }

    return $value;
  }
}

/**
 * Here's how one of the classes we delegate to might look.
 */
class Sunrise_Fields {
  private $_fields = array();

  function register( $field_name, $args ) {
    $this->_fields[$field_name] = new Sunrise_Field( $field_name, $args );
  }
  function __construct() {
    add_action( 'init', array( $this, 'init' ) );
  }
  function init() {
    $sunrise = Sunrise::get_instance();
    $sunrise->register_delegate( 'register_field', array( $this, 'register' ) );
  }
}
new Sunrise_Fields();

/**
 * This is how we might use it in an application plugin
 */
$sunrise = Sunrise::get_instance();
$sunrise->register_field( 'birthday', array( 'type' => 'date' ) );

/**
 * Or just:
 */
Sunrise::get_instance()->register_field( 'birthday', array( 'type' => 'date' ) );