1 package java_cup;
2 
3 /** This class represents one part (either a symbol or an action) of a
4  *  production.  In this base class it contains only an optional label
5  *  string that the user can use to refer to the part within actions.<p>
6  *
7  *  This is an abstract class.
8  *
9  * @see     java_cup.production
10  * @version last updated: 11/25/95
11  * @author  Scott Hudson
12  */
13 public abstract class production_part {
14 
15   /*-----------------------------------------------------------*/
16   /*--- Constructor(s) ----------------------------------------*/
17   /*-----------------------------------------------------------*/
18 
19   /** Simple constructor. */
production_part(String lab)20   public production_part(String lab)
21     {
22       _label = lab;
23     }
24 
25   /*-----------------------------------------------------------*/
26   /*--- (Access to) Instance Variables ------------------------*/
27   /*-----------------------------------------------------------*/
28 
29   /** Optional label for referring to the part within an action (null for
30    *  no label).
31    */
32   protected String _label;
33 
34   /** Optional label for referring to the part within an action (null for
35    *  no label).
36    */
label()37   public String label() {return _label;}
38 
39   /*-----------------------------------------------------------*/
40   /*--- General Methods ---------------------------------------*/
41   /*-----------------------------------------------------------*/
42 
43   /** Indicate if this is an action (rather than a symbol).  Here in the
44    * base class, we don't this know yet, so its an abstract method.
45    */
is_action()46   public abstract boolean is_action();
47 
48   /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
49 
50   /** Equality comparison. */
equals(production_part other)51   public boolean equals(production_part other)
52     {
53       if (other == null) return false;
54 
55       /* compare the labels */
56       if (label() != null)
57 	return label().equals(other.label());
58       else
59 	return other.label() == null;
60     }
61 
62   /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
63 
64   /** Generic equality comparison. */
equals(Object other)65   public boolean equals(Object other)
66     {
67       if (!(other instanceof production_part))
68         return false;
69       else
70 	return equals((production_part)other);
71     }
72 
73   /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
74 
75   /** Produce a hash code. */
hashCode()76   public int hashCode()
77     {
78       return label()==null ? 0 : label().hashCode();
79     }
80 
81   /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
82 
83   /** Convert to a string. */
toString()84   public String toString()
85     {
86       if (label() != null)
87 	return label() + ":";
88       else
89 	return " ";
90     }
91 
92   /*-----------------------------------------------------------*/
93 
94 };
95