/* NSC -- new Scala compiler
 * Copyright 2005-2011 LAMP/EPFL
 * @author  Martin Odersky
 */

package scala.tools.nsc
package util

import scala.collection.mutable.HashMap

trait FreshNameCreator {
  /** Do not call before after type checking ends.
   *  PP: I think that directive needs to lose a word somewhere.
   */
  def newName(): String
  def newName(prefix: String): String

  @deprecated("use newName(prefix)", "2.9.0")
  def newName(pos: util.Position, prefix: String): String = newName(prefix)
  @deprecated("use newName()", "2.9.0")
  def newName(pos: util.Position): String = newName()
}

object FreshNameCreator {  
  class Default extends FreshNameCreator {
    protected var counter = 0
    protected val counters = new HashMap[String, Int] withDefaultValue 0

    /**
     * Create a fresh name with the given prefix. It is guaranteed
     * that the returned name has never been returned by a previous
     * call to this function (provided the prefix does not end in a digit).
     */
    def newName(prefix: String): String = {
      val safePrefix = prefix.replaceAll("""[<>]""", """\$""")
      counters(safePrefix) += 1
      
      safePrefix + counters(safePrefix)
    }
    def newName(): String = {
      counter += 1
      "$" + counter + "$"
    }
  }
}