path: root/src/library/scala/Symbol.scala

/*                     __                                               *\
**     ________ ___   / /  ___     Scala API                            **
**    / __/ __// _ | / /  / _ |    (c) 2003-2006, LAMP/EPFL             **
**  __\ \/ /__/ __ |/ /__/ __ |                                         **
** /____/\___/_/ |_/____/_/ | |                                         **
**                          |/                                          **
\*                                                                      */

// $Id$


package scala;

import collection.jcl.WeakHashMap

private[scala] object internedSymbols extends WeakHashMap[String, Symbol]

/** Instances of <code>Symbol</code> can be created easily with
 *  Scala's built-in quote mechanism. For instance, the Scala term
 *  <code>'mysym</code> will invoke the constructor of the
 *  <code>Symbol</code> class in the following way:
 *  <code>new Symbol("mysym")</code>. .
 *
 *  @author  Martin Odersky
 *  @version 1.7, 08/12/2003
 */
final case class Symbol(name: String) {

  /** Converts this symbol to a string.
   */
  override def toString(): String = {
    "'" + name
  }

  /** Makes this symbol into a unique reference.
   *  If two interened symbols are equal (i.e. they have the same name)
   *  then they must be identical (wrt reference equality)
   */
  def intern: Symbol = internedSymbols get name match {
    case Some(sym) =>
      sym
    case None =>
      internedSymbols(name) = this
      this
  }
}