src/library/scala/PartialFunction.scala


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/*                     __                                               *\
**     ________ ___   / /  ___     Scala API                            **
**    / __/ __// _ | / /  / _ |    (c) 2002-2003, LAMP/EPFL             **
**  __\ \/ /__/ __ |/ /__/ __ |                                         **
** /____/\___/_/ |_/____/_/ | |                                         **
**                          |/                                          **
** $Id:PartialFunction.scala 5359 2005-12-16 16:33:49 +0100 (Fri, 16 Dec 2005) dubochet $
\*                                                                      */

package scala;


/** A partial function of type <code>PartialFunction[A, B]</code> is a
 *  unary function where the domain does not include all values of type
 *  <code>A</code>. The function <code>isDefinedAt</code> allows to
 *  test dynamically, if a value is in the domain of the function.
 *
 *  @author  Martin Odersky
 *  @version 1.0, 16/07/2003
 */
trait PartialFunction[-A, +B] extends AnyRef with Function1[A, B] {

    /** Checks if a value is contained in the functions domain.
     *
     *  @param  x   the value to test
     *  @return true, iff <code>x</code> is in the domain of this function.
     */
    def isDefinedAt(x: A): Boolean;
}