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Java > Open Source Codes > com > sun > java_cup > internal > parse_action


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 JavaDoc 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 JavaDoc toString() {return "ERROR";}
89
90   /*-----------------------------------------------------------*/
91 }
92     
93
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