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


1
2 package com.sun.java_cup.internal;
3
4 import java.util.Enumeration JavaDoc;
5
6 /** This class represents the complete "reduce-goto" table of the parser.
7  * It has one row for each state in the parse machines, and a column for
8  * each terminal symbol. Each entry contains a state number to shift to
9  * as the last step of a reduce.
10  *
11  * @see com.sun.java_cup.internal.parse_reduce_row
12  * @version last updated: 11/25/95
13  * @author Scott Hudson
14  */
15 public class parse_reduce_table {
16  
17   /*-----------------------------------------------------------*/
18   /*--- Constructor(s) ----------------------------------------*/
19   /*-----------------------------------------------------------*/
20
21   /** Simple constructor. Note: all terminals, non-terminals, and productions
22    * must already have been entered, and the viable prefix recognizer should
23    * have been constructed before this is called.
24    */
25   public parse_reduce_table()
26     {
27       /* determine how many states we are working with */
28       _num_states = lalr_state.number();
29
30       /* allocate the array and fill it in with empty rows */
31       under_state = new parse_reduce_row[_num_states];
32       for (int i=0; i<_num_states; i++)
33     under_state[i] = new parse_reduce_row();
34     }
35
36    
37   /*-----------------------------------------------------------*/
38   /*--- (Access to) Instance Variables ------------------------*/
39   /*-----------------------------------------------------------*/
40
41   /** How many rows/states in the machine/table. */
42   protected int _num_states;
43
44   /** How many rows/states in the machine/table. */
45   public int num_states() {return _num_states;}
46
47   /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
48
49   /** Actual array of rows, one per state */
50   public parse_reduce_row[] under_state;
51  
52   /*-----------------------------------------------------------*/
53   /*--- General Methods ---------------------------------------*/
54   /*-----------------------------------------------------------*/
55
56   /** Convert to a string. */
57   public String JavaDoc toString()
58     {
59       String JavaDoc result;
60       lalr_state goto_st;
61       int cnt;
62
63       result = "-------- REDUCE_TABLE --------\n";
64       for (int row = 0; row < num_states(); row++)
65     {
66       result += "From state #" + row + "\n";
67       cnt = 0;
68       for (int col = 0; col < under_state[row].size(); col++)
69         {
70           /* pull out the table entry */
71           goto_st = under_state[row].under_non_term[col];
72
73           /* if it has action in it, print it */
74           if (goto_st != null)
75         {
76           result += " [non term " + col + "->";
77           result += "state " + goto_st.index() + "]";
78
79           /* end the line after the 3rd one */
80           cnt++;
81           if (cnt == 3)
82             {
83               result += "\n";
84               cnt = 0;
85             }
86         }
87         }
88           /* finish the line if we haven't just done that */
89       if (cnt != 0) result += "\n";
90     }
91       result += "-----------------------------";
92
93       return result;
94     }
95
96   /*-----------------------------------------------------------*/
97
98 }
99
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