 }
 
 
+/**
+ * Returns a virtual property of an object.  A virtual property is an
+ * intermediate abstraction that does not exist in the runtime, but will later
+ * be transformed into runtime terms by the VirtualGetResolver AST filter.
+ *
+ * Virtual property  |  X axis   |  Transformed into
+ * MID               |  HCENTER  |  object.x + object.width * 0.5
+ * MAX               |  RIGHT    |  object.x + object.width
+ */
 class GetVirtualProp implements ASTNode
 {
     public var object:Object;

}


class SetVirtualProps implements ASTNode
{
    public var object:Object;

}


/**
 * Rounds the value of a node to the nearest integer, with half-integer values
 * rounding towards positive infinity.
 */
class Round implements ASTNode
{
    public var child:ASTNode;
