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. 
 * 
 * @see     java_cup.reduce_action
 * @see     java_cup.shift_action
 * @version last updated: 7/2/96
 * @author  Frank Flannery
 */

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

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

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

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

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

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