RegularExpression


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22  
23  package org.javacc.parser;
24  
25  /**
26   * Describes regular expressions.
27   */
28  
29  abstract public class RegularExpression extends Expansion {
30  
31    /**
32     * The label of the regular expression (if any).  If no label is
33     * present, this is set to "".
34     */
35    public String   label = "";
36  
37    /**
38     * The ordinal value assigned to the regular expression.  It is
39     * used for internal processing and passing information between
40     * the parser and the lexical analyzer.
41     */
42    int ordinal;
43  
44    /**
45     * The LHS to which the token value of the regular expression
46     * is assigned.  In case there is no LHS, then the vector
47     * remains empty.
48     */
49    public java.util.Vector   lhsTokens = new java.util.Vector  ();
50  
51    /**
52      * We now allow qualified access to token members. Store it here.
53     */
54    public Token rhsToken;
55  
56    /**
57     * This flag is set if the regular expression has a label prefixed
58     * with the # symbol - this indicates that the purpose of the regular
59     * expression is solely for defining other regular expressions.
60     */
61    public boolean private_rexp = false;
62  
63    /**
64     * If this is a top-level regular expression (nested directly
65     * within a TokenProduction), then this field point to that
66     * TokenProduction object.
67     */
68    public TokenProduction tpContext = null;
69  
70    abstract public Nfa GenerateNfa(boolean ignoreCase);
71  
72    public boolean CanMatchAnyChar()
73    {
74       return false;
75    }
76  
77    /**
78     * The following variable is used to maintain state information for the
79     * loop determination algorithm:  It is initialized to 0, and
80     * set to -1 if this node has been visited in a pre-order walk, and then
81     * it is set to 1 if the pre-order walk of the whole graph from this
82     * node has been traversed.  i.e., -1 indicates partially processed,
83     * and 1 indicates fully processed.
84     */
85    int walkStatus = 0;
86  
87  }
88
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