Simplified Sortable Interface

gistfile1.php

<?php

/** 
 * This Interface allows to hook into the global Xsort() functions.
 * @ingroup SPL
 * @since PHP 7.0
 */
interface Sortable
{
  /**
   * Sort the entries by values.
   *
   * @param callable $cmp_function
   * For usort(), will be passed the user's comparison callback.
   * For sort(), rsort(), natsort(), natcasesort(), will be passed a comparison defined by the engine.
   */
  public function sortValues(callable $cmp_function);
  
  /**
   * Sort the entries by values and maintain indexes.
   *
   * @param callable $cmp_function
   * For uasort(), will be passed the user's comparison callback.
   * For asort(), arsort(), will be passed a comparison defined by the engine.
   */
  public function sortValuesAssoc(callable $cmp_function);
  
  /**
   * Sort the entries by key.
   *
   * @param callable $cmp_function
   * For uksort(), will be passed the user's comparison callback.
   * For ksort(), krsort(), will be passed a comparison defined by the engine.
   */
  public function sortKeys(callable $cmp_function);
}