java_cup.parse_action Maven / Gradle / Ivy

Go to download
package java_cup;

/**
 * This class serves as the base class for entries in a parse action table.
 * Full entries will either be SHIFT(state_num), REDUCE(production), NONASSOC,
 * or ERROR. Objects of this base class will default to ERROR, while
 * the other three types will be represented by subclasses.
 *
 * @author Frank Flannery
 * @version last updated: 7/2/96
 * @see java_cup.reduce_action
 * @see java_cup.shift_action
 */

public class parse_action {

  /*-----------------------------------------------------------*/
  /*--- Constructor(s) ----------------------------------------*/
  /*-----------------------------------------------------------*/

    /**
     * Simple constructor.
     */
    public parse_action() {
      /* nothing to do in the base class */
    }

 
  /*-----------------------------------------------------------*/
  /*--- (Access to) Static (Class) Variables ------------------*/
  /*-----------------------------------------------------------*/

    /**
     * Constant for action type -- error action.
     */
    public static final int ERROR = 0;

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

    /**
     * Constant for action type -- shift action.
     */
    public static final int SHIFT = 1;

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

    /**
     * Constants for action type -- reduce action.
     */
    public static final int REDUCE = 2;

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

    /**
     * Constants for action type -- reduce action.
     */
    public static final int NONASSOC = 3;

  /*-----------------------------------------------------------*/
  /*--- General Methods ---------------------------------------*/
  /*-----------------------------------------------------------*/

    /**
     * Quick access to the type -- base class defaults to error.
     */
    public int kind() {
        return ERROR;
    }

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

    /**
     * Equality test.
     */
    public boolean equals(parse_action other) {
      /* we match all error actions */
        return other != null && other.kind() == ERROR;
    }

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

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

    /**
     * Compute a hash code.
     */
    public int hashCode() {
      /* all objects of this class hash together */
        return 0xCafe123;
    }

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

    /**
     * Convert to string.
     */
    public String toString() {
        return "ERROR";
    }

  /*-----------------------------------------------------------*/
}