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    */
reduce_action(production prod )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. */
reduce_with()38   public production reduce_with() {return _reduce_with;}
39 
40   /*-----------------------------------------------------------*/
41   /*--- General Methods ---------------------------------------*/
42   /*-----------------------------------------------------------*/
43 
44   /** Quick access to type of action. */
kind()45   public int kind() {return REDUCE;}
46 
47   /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
48 
49   /** Equality test. */
equals(reduce_action other)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. */
equals(Object other)58   public boolean equals(Object 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. */
hashCode()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. */
toString()77   public String toString()
78     {
79       return "REDUCE(" + reduce_with().index() + ")";
80     }
81 
82   /*-----------------------------------------------------------*/
83 
84 };
85