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Java > Open Source Codes > antlr > GrammarElement


1 package antlr;
2
3 /* ANTLR Translator Generator
4  * Project led by Terence Parr at http://www.jGuru.com
5  * Software rights: http://www.antlr.org/RIGHTS.html
6  *
7  * $Id: //depot/code/org.antlr/main/main/antlr/GrammarElement.java#6 $
8  */
9
10 /**A GrammarElement is a generic node in our
11  * data structure that holds a grammar in memory.
12  * This data structure can be used for static
13  * analysis or for dynamic analysis (during parsing).
14  * Every node must know which grammar owns it, how
15  * to generate code, and how to do analysis.
16  */
17 abstract class GrammarElement {
18     public static final int AUTO_GEN_NONE = 1;
19     public static final int AUTO_GEN_CARET = 2;
20     public static final int AUTO_GEN_BANG = 3;
21
22     /*
23      * Note that Java does static argument type matching to
24      * determine which function to execute on the receiver.
25      * Here, that implies that we cannot simply say
26      * grammar.generator.gen(this) in GrammarElement or
27      * only CodeGenerator.gen(GrammarElement ge) would
28      * ever be called.
29      */
30     protected Grammar grammar;
31     protected int line;
32     protected int column;
33
34     public GrammarElement(Grammar g) {
35         grammar = g;
36         line = -1;
37         column = -1;
38     }
39
40     public GrammarElement(Grammar g, Token start) {
41         grammar = g;
42         line = start.getLine();
43         column = start.getColumn();
44     }
45
46     public void generate() {
47     }
48
49     public int getLine() {
50         return line;
51     }
52
53     public int getColumn() {
54         return column;
55     }
56
57     public Lookahead look(int k) {
58         return null;
59     }
60
61     public abstract String JavaDoc toString();
62 }
63
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