}
/**
- * Append to XML response based on given arguments.
+ * Appends data to an XML response based on given arguments.
*
- * The arguments that can be passed in the $args parameter are below. It is
- * also possible to pass a WP_Error object in either the 'id' or 'data'
- * argument. The parameter isn't actually optional, content should be given
- * in order to send the correct response.
+ * With `$args` defaults, extra data output would be:
*
- * 'what' argument is a string that is the XMLRPC response type.
- * 'action' argument is a boolean or string that acts like a nonce.
- * 'id' argument can be WP_Error or an integer.
- * 'old_id' argument is false by default or an integer of the previous ID.
- * 'position' argument is an integer or a string with -1 = top, 1 = bottom,
- * html ID = after, -html ID = before.
- * 'data' argument is a string with the content or message.
- * 'supplemental' argument is an array of strings that will be children of
- * the supplemental element.
+ * <response action='{$action}_$id'>
+ * <$what id='$id' position='$position'>
+ * <response_data><![CDATA[$data]]></response_data>
+ * </$what>
+ * </response>
*
* @since 2.1.0
+ * @access public
*
- * @param string|array $args Override defaults.
+ * @param string|array $args {
+ * Optional. An array or string of XML response arguments.
+ *
+ * @type string $what XML-RPC response type. Used as a child element of `<response>`.
+ * Default 'object' (`<object>`).
+ * @type string|false $action Value to use for the `action` attribute in `<response>`. Will be
+ * appended with `_$id` on output. If false, `$action` will default to
+ * the value of `$_POST['action']`. Default false.
+ * @type int|WP_Error $id The response ID, used as the response type `id` attribute. Also
+ * accepts a `WP_Error` object if the ID does not exist. Default 0.
+ * @type int|false $old_id The previous response ID. Used as the value for the response type
+ * `old_id` attribute. False hides the attribute. Default false.
+ * @type string $position Value of the response type `position` attribute. Accepts 1 (bottom),
+ * -1 (top), html ID (after), or -html ID (before). Default 1 (bottom).
+ * @type string|WP_Error $data The response content/message. Also accepts a WP_Error object if the
+ * ID does not exist. Default empty.
+ * @type array $supplemental An array of extra strings that will be output within a `<supplemental>`
+ * element as CDATA. Default empty array.
+ * }
* @return string XML response.
*/
public function add( $args = '' ) {