/*                     __                                               *\
**     ________ ___   / /  ___     Scala API                            **
**    / __/ __// _ | / /  / _ |    (c) 2003, LAMP/EPFL                  **
**  __\ \/ /__/ __ |/ /__/ __ |                                         **
** /____/\___/_/ |_/____/_/ | |                                         **
**                          |/                                          **
\*                                                                      */

// $Id$

package scala;


/**
 * Collection classes supporting this trait provide a method
 * <code>elements</code> which returns an iterator over all the
 * elements contained in the collection.
 *
 * @author  Matthias Zenger
 * @version 1.0, 16/07/2003
 */
trait StructuralEquality[+A <: StructuralEquality[A]] {

    /**
     * Compares this object with the provided object structurally;
     * i.e. by looking at the internal structure of aggregated objects.
     * <code>===</code> does not have to be compatible with the
     * <code>hashCode</code> method.
     *
     * @param  that	the other object
     * @return true, iff <code>this</code> and <code>that</code> are
     *         structurally equivalent.
     */
    def ===[B >: A](that: B): Boolean = (this == that);

    /**
     * Compares this object with the provided object structurally
     * and returns true, iff the two objects differ.
     *
     * @param  that	the other object
     * @return false, iff <code>this</code> and <code>that</code> are
     *         structurally equivalent.
     */
    def !==[B >: A](that: B): Boolean = !(this === that);

}