Index: wp-includes/class.wp-dependencies.php
===================================================================
--- wp-includes/class.wp-dependencies.php	(revision 23883)
+++ wp-includes/class.wp-dependencies.php	(working copy)
@@ -21,27 +21,35 @@
 	var $queue = array();
 	var $to_do = array();
 	var $done = array();
-	var $args = array();
-	var $groups = array();
-	var $group = 0;
+	var $args = array();  // In extending classes, strings appended to item urls.
+	var $groups = array();  // In extending class WP_Scripts, header and footer groups.
+	var $group = 0;  // Internal group state.
 
 	/**
 	 * Do the dependencies
 	 *
-	 * Process the items passed to it or the queue. Processes all dependencies.
+	 * Processes the items passed to it or the queue. Processes all dependencies.
 	 *
-	 * @param mixed $handles (optional) items to be processed. (void) processes queue, (string) process that item, (array of strings) process those items
-	 * @return array Items that have been processed
+	 * @param mixed $handles (optional) Items to be processed: (false) Process queue, (string) process item, (array of strings) process items
+	 * @param mixed $group Group level: (int) level, (false) no groups
+	 * @return array Handles of items that have been processed
 	 */
 	function do_items( $handles = false, $group = false ) {
-		// Print the queue if nothing is passed. If a string is passed, print that script. If an array is passed, print those scripts.
+		// Print the queue if nothing is passed. If a string is passed, print that item. If an array is passed, print those items.
 		$handles = false === $handles ? $this->queue : (array) $handles;
 		$this->all_deps( $handles );
 
 		foreach( $this->to_do as $key => $handle ) {
 			if ( !in_array($handle, $this->done, true) && isset($this->registered[$handle]) ) {
 
-				if ( ! $this->registered[$handle]->src ) { // Defines a group.
+				/**
+				 * A single item may alias a set of items, by having dependencies but no src.
+				 * Queuing the item queues the dependencies.
+				 * Example: the extending class WP_Scripts is used to register 'scriptaculous' as a set of registered handles:
+				 *   add( 'scriptaculous', false, array('scriptaculous-dragdrop', 'scriptaculous-slider', 'scriptaculous-controls') );
+				 * The src property is false.
+				**/
+				if ( ! $this->registered[$handle]->src ) {
 					$this->done[] = $handle;
 					continue;
 				}
@@ -56,18 +64,28 @@
 		return $this->done;
 	}
 
+	/**
+	 * Do dependency
+	 *
+	 * Processes one item for dependencies.
+	 *
+	 * @param string $handle Unique item name
+	 * @return bool Success
+	 */
 	function do_item( $handle ) {
 		return isset($this->registered[$handle]);
 	}
 
 	/**
-	 * Determines dependencies
+	 * Determine dependencies
 	 *
-	 * Recursively builds array of items to process taking dependencies into account. Does NOT catch infinite loops.
+	 * Recursively builds array of items to process taking dependencies into account.
+	 * Does NOT catch infinite loops.
 	 *
-	 *
-	 * @param mixed $handles Accepts (string) dep name or (array of strings) dep names
-	 * @param bool $recursion Used internally when function calls itself
+	 * @param mixed $handles (string) Dependency handle and argument or (array of strings) Dependency handles and arguments
+	 * @param bool $recursion Internal flag that function is calling itself
+	 * @param mixed $group Group level: (int) level, (false) no groups
+	 * @return bool Success
 	 */
 	function all_deps( $handles, $recursion = false, $group = false ) {
 		if ( !$handles = (array) $handles )
@@ -88,13 +106,13 @@
 
 			$keep_going = true;
 			if ( !isset($this->registered[$handle]) )
-				$keep_going = false; // Script doesn't exist
+				$keep_going = false; // Item doesn't exist
 			elseif ( $this->registered[$handle]->deps && array_diff($this->registered[$handle]->deps, array_keys($this->registered)) )
-				$keep_going = false; // Script requires deps which don't exist (not a necessary check. efficiency?)
+				$keep_going = false; // Item requires deps which don't exist (not a necessary check. efficiency?)
 			elseif ( $this->registered[$handle]->deps && !$this->all_deps( $this->registered[$handle]->deps, true, $group ) )
-				$keep_going = false; // Script requires deps which don't exist
+				$keep_going = false; // Item requires deps which don't exist
 
-			if ( !$keep_going ) { // Either script or its deps don't exist.
+			if ( !$keep_going ) { // Either item or its deps don't exist.
 				if ( $recursion )
 					return false; // Abort this branch.
 				else
@@ -114,15 +132,16 @@
 	}
 
 	/**
-	 * Adds item
+	 * Register item
 	 *
-	 * Adds the item only if no item of that name already exists
+	 * Registers the item if no item of that name already exists.
 	 *
-	 * @param string $handle Script name
-	 * @param string $src Script url
-	 * @param array $deps (optional) Array of script names on which this script depends
-	 * @param string $ver (optional) Script version (used for cache busting)
-	 * @return array Hierarchical array of dependencies
+	 * @param string $handle Unique item name
+	 * @param string $src Resource url
+	 * @param array of strings $deps (optional) Item handles on which this item depends
+	 * @param string $ver (optional) Version (used for cache busting)
+	 * @param mixed $args (optional) Custom property of the item. NOT the class property $args. Examples: $media, $in_footer.
+	 * @return bool Success
 	 */
 	function add( $handle, $src, $deps = array(), $ver = false, $args = null ) {
 		if ( isset($this->registered[$handle]) )
@@ -132,14 +151,14 @@
 	}
 
 	/**
-	 * Adds extra data
+	 * Add extra data
 	 *
-	 * Adds data only if script has already been added.
+	 * Adds data if item has been registered.
 	 *
-	 * @param string $handle Script name
-	 * @param string $key
-	 * @param mixed $value
-	 * @return bool success
+	 * @param string $handle Unique item name
+	 * @param string $key Data key
+	 * @param mixed $value Data value
+	 * @return bool Success
 	 */
 	function add_data( $handle, $key, $value ) {
 		if ( !isset( $this->registered[$handle] ) )
@@ -151,13 +170,13 @@
 	/**
 	 * Get extra data
 	 *
-	 * Gets data associated with a certain handle.
+	 * Gets data associated with a registered item.
 	 *
 	 * @since WP 3.3
 	 *
-	 * @param string $handle Script name
-	 * @param string $key
-	 * @return mixed
+	 * @param string $handle Unique item name
+	 * @param string $key Data key
+	 * @return mixed Data value
 	 */
 	function get_data( $handle, $key ) {
 		if ( !isset( $this->registered[$handle] ) )
@@ -169,11 +188,27 @@
 		return $this->registered[$handle]->extra[$key];
 	}
 
+	/**
+	 * Unregister items
+	 *
+	 * @param mixed $handles (string) Item handle or (array of strings) Item handles
+	 * @return void
+	 */
 	function remove( $handles ) {
 		foreach ( (array) $handles as $handle )
 			unset($this->registered[$handle]);
 	}
 
+	/**
+	 * Queue items
+	 *
+	 * Decode handle and argument, then queue handle and store argument in the class property $args.
+	 * For example, in extending classes, $args is appended to the item url.
+	 * Note $args is NOT the $args property of items in the $registered array.
+	 *
+	 * @param mixed $handles (string) Item handle and argument or (array of strings) Item handles and arguments
+	 * @return void
+	 */
 	function enqueue( $handles ) {
 		foreach ( (array) $handles as $handle ) {
 			$handle = explode('?', $handle);
@@ -185,6 +220,14 @@
 		}
 	}
 
+	/**
+	 * Dequeue items
+	 *
+	 * Decode handle and argument, then dequeue handle and remove argument from the class property $args.
+	 *
+	 * @param mixed $handles (string) Item handle and argument or (array of strings) Item handles and arguments
+	 * @return void
+	 */
 	function dequeue( $handles ) {
 		foreach ( (array) $handles as $handle ) {
 			$handle = explode('?', $handle);
@@ -196,7 +239,12 @@
 		}
 	}
 
-
+	/**
+	 * Query list for item
+	 *
+	 * @param $handle (string) Item handle
+	 * @return bool Found, or object Item data
+	 */
 	function query( $handle, $list = 'registered' ) {
 		switch ( $list ) {
 			case 'registered' :
@@ -220,6 +268,14 @@
 		return false;
 	}
 
+	/**
+	 * Set item group, unless already in a lower group
+	 *
+	 * @param $handle (string) Item handle
+	 * @param bool $recursion Internal flag that calling function was called recusively
+	 * @param mixed $group Group level
+	 * @return bool Not already in the group or a lower group
+	 */
 	function set_group( $handle, $recursion, $group ) {
 		$group = (int) $group;
 
@@ -242,8 +298,7 @@
 	var $src;
 	var $deps = array();
 	var $ver = false;
-	var $args = null;
-
+	var $args = null;  // Custom property, such as $in_footer or $media.
 	var $extra = array();
 
 	function __construct() {