
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. */
  @Override
  public int kind() {
    return REDUCE;
  }

  /* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . */

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

  /* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . */

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

  /* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . */

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

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

  /*-----------------------------------------------------------*/

}
