1. 

  2. package com.sun.java_cup.internal;

  3. 

  4. /** This class serves as the base class for entries in a parse action table.  

  5.  *  Full entries will either be SHIFT(state_num), REDUCE(production), NONASSOC,

  6.  *  or ERROR. Objects of this base class will default to ERROR, while

  7.  *  the other three types will be represented by subclasses. 

  8.  * 

  9.  * @see     com.sun.java_cup.internal.reduce_action

  10.  * @see     com.sun.java_cup.internal.shift_action

  11.  * @version last updated: 7/2/96

  12.  * @author  Frank Flannery

  13.  */

  14. 

  15. public class parse_action {

  16. 

  17.   /*-----------------------------------------------------------*/

  18.   /*--- Constructor(s) ----------------------------------------*/

  19.   /*-----------------------------------------------------------*/

  20. 

  21.   /** Simple constructor. */

  22.   public parse_action()

  23.     {

  24.       /* nothing to do in the base class */

  25.     }

  26. 

  27.  

  28.   /*-----------------------------------------------------------*/

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

  30.   /*-----------------------------------------------------------*/

  31. 

  32.   /** Constant for action type -- error action. */

  33.   public static final int ERROR = 0;

  34. 

  35.   /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/

  36. 

  37.   /** Constant for action type -- shift action. */

  38.   public static final int SHIFT = 1;

  39. 

  40.   /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/

  41. 

  42.   /** Constants for action type -- reduce action. */

  43.   public static final int REDUCE = 2;

  44. 

  45.   /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/

  46. 

  47.   /** Constants for action type -- reduce action. */

  48.   public static final int NONASSOC = 3;

  49. 

  50.   /*-----------------------------------------------------------*/

  51.   /*--- General Methods ---------------------------------------*/

  52.   /*-----------------------------------------------------------*/

  53. 	 

  54.   /** Quick access to the type -- base class defaults to error. */

  55.   public int kind() {return ERROR;}

  56. 

  57.   /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/

  58. 

  59.   /** Equality test. */

  60.   public boolean equals(parse_action other)

  61.     {

  62.       /* we match all error actions */

  63.       return other != null && other.kind() == ERROR;

  64.     }

  65. 

  66.   /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/

  67. 

  68.   /** Generic equality test. */

  69.   public boolean equals(Object other)

  70.     {

  71.       if (other instanceof parse_action)

  72. 	return equals((parse_action)other);

  73.       else

  74. 	return false;

  75.     }

  76.   /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/

  77. 

  78.   /** Compute a hash code. */

  79.   public int hashCode()

  80.     {

  81.       /* all objects of this class hash together */

  82.       return 0xCafe123;

  83.     }

  84. 

  85.   /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/

  86. 

  87.   /** Convert to string. */

  88.   public String toString() {return "ERROR";}

  89. 

  90.   /*-----------------------------------------------------------*/

  91. }

  92.