reduce_action.java

package java_cup ;


/**
 * This class represents a reduce action within the parse table. The action
 * simply stores the production that it reduces with and responds to queries
 * about its type.
 * 
 * @version last updated: 11/25/95
 * @author Scott Hudson
 */
public class reduce_action extends parse_action
{
  /*-----------------------------------------------------------*/
  /*--- Constructor(s) ----------------------------------------*/
  /*-----------------------------------------------------------*/
  /**
   * Simple constructor.
   * 
   * @param prod the production this action reduces with.
   */
  public reduce_action ( production prod ) throws internal_error
  {
    /* sanity check */
    if ( prod == null )
      throw new internal_error (
          "Attempt to create a reduce_action with a null production" ) ;
    _reduce_with = prod ;
  }


  /*-----------------------------------------------------------*/
  /*--- (Access to) Instance Variables ------------------------*/
  /*-----------------------------------------------------------*/
  /** The production we reduce with. */
  protected production _reduce_with ;


  /** The production we reduce with. */
  public production reduce_with ( )
  {
    return _reduce_with ;
  }


  /*-----------------------------------------------------------*/
  /*--- General Methods ---------------------------------------*/
  /*-----------------------------------------------------------*/
  /** Quick access to type of action. */
  public int kind ( )
  {
    return REDUCE ;
  }


  /* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . */
  /** Equality test. */
  public boolean equals ( reduce_action other )
  {
    return other != null && other.reduce_with ( ) == reduce_with ( ) ;
  }


  /* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . */
  /** Generic equality test. */
  public boolean equals ( Object other )
  {
    if ( other instanceof reduce_action )
      return equals ( ( reduce_action ) other ) ;
    else return false ;
  }


  /* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . */
  /** Compute a hash code. */
  public int hashCode ( )
  {
    /* use the hash code of the production we are reducing with */
    return reduce_with ( ).hashCode ( ) ;
  }


  /** Convert to string. */
  public String toString ( )
  {
    return "REDUCE(with prod " + reduce_with ( ).index ( ) + ")" ;
  }
  /*-----------------------------------------------------------*/
}