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Java > Open Source Codes > java_cup > reduce_action


1
2 package java_cup;
3
4 /** This class represents a reduce action within the parse table.
5  * The action simply stores the production that it reduces with and
6  * responds to queries about its type.
7  *
8  * @version last updated: 11/25/95
9  * @author Scott Hudson
10  */

11 public class reduce_action extends parse_action {
12  
13   /*-----------------------------------------------------------*/
14   /*--- Constructor(s) ----------------------------------------*/
15   /*-----------------------------------------------------------*/
16
17   /** Simple constructor.
18    * @param prod the production this action reduces with.
19    */

20   public reduce_action(production prod ) throws internal_error
21     {
22       /* sanity check */
23       if (prod == null)
24     throw new internal_error(
25       "Attempt to create a reduce_action with a null production");
26
27       _reduce_with = prod;
28     }
29
30   /*-----------------------------------------------------------*/
31   /*--- (Access to) Instance Variables ------------------------*/
32   /*-----------------------------------------------------------*/
33   
34   /** The production we reduce with. */
35   protected production _reduce_with;
36
37   /** The production we reduce with. */
38   public production reduce_with() {return _reduce_with;}
39
40   /*-----------------------------------------------------------*/
41   /*--- General Methods ---------------------------------------*/
42   /*-----------------------------------------------------------*/
43
44   /** Quick access to type of action. */
45   public int kind() {return REDUCE;}
46
47   /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
48
49   /** Equality test. */
50   public boolean equals(reduce_action other)
51     {
52       return other != null && other.reduce_with() == reduce_with();
53     }
54
55   /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
56
57   /** Generic equality test. */
58   public boolean equals(Object JavaDoc other)
59     {
60       if (other instanceof reduce_action)
61     return equals((reduce_action)other);
62       else
63        return false;
64     }
65
66   /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
67
68   /** Compute a hash code. */
69   public int hashCode()
70     {
71       /* use the hash code of the production we are reducing with */
72       return reduce_with().hashCode();
73     }
74
75
76   /** Convert to string. */
77   public String JavaDoc toString()
78     {
79       return "REDUCE(with prod " + reduce_with().index() + ")";
80     }
81
82   /*-----------------------------------------------------------*/
83
84 }
85
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