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package EDU.purdue.jtb.parser;

import java.util.ArrayList;
import java.util.List;
import java.util.Set;

/**
 * Describes regular expressions.
 * 
 * @author Marc Mazas
 * @version 1.4.0 : 05/2009 : MMa : adapted to JavaCC v4.2 grammar
 * @version 1.4.8 : 12/2014 : MMa : improved javadoc ; remove local variable ordinal hiding
 *          superclass's one
 */
public abstract class RegularExpression_ extends Expansion_ {

  /**
   * The label of the regular expression (if any). If no label is present, this is set to "".
   */
  public String          label        = "";
  //  /**
  //   * The ordinal value assigned to the regular expression. It is used for internal processing and
  //   * passing information between the parser and the lexical analyzer.
  //   */
  //  // hides Expansion_.ordinal !!!
  //  int                    ordinal;
  /**
   * The LHS to which the token value of the regular expression is assigned. In case there is no
   * LHS, then the list remains empty.
   */
  public List<Token>     lhsTokens    = new ArrayList<Token>();
  /**
   * We now allow qualified access to token members. Store it here.
   */
  public Token           rhsToken;
  /**
   * This flag is set if the regular expression has a label prefixed with the # symbol - this
   * indicates that the purpose of the regular expression is solely for defining other regular
   * expressions.
   */
  public boolean         private_rexp = false;
  /**
   * If this is a top-level regular expression (nested directly within a TokenProduction), then this
   * field point to that TokenProduction object.
   */
  public TokenProduction tpContext    = null;

  /**
   * @param ignoreCase - true to ignore case
   * @return the generated NFA
   */
  public abstract Nfa GenerateNfa(boolean ignoreCase);

  /**
   * @return always false
   */
  @SuppressWarnings("static-method")
  public boolean CanMatchAnyChar() {
    return false;
  }

  /**
   * The following variable is used to maintain state information for the loop determination
   * algorithm: It is initialized to 0, and set to -1 if this node has been visited in a pre-order
   * walk, and then it is set to 1 if the pre-order walk of the whole graph from this node has been
   * traversed. i.e., -1 indicates partially processed, and 1 indicates fully processed.
   */
  int walkStatus = 0;

  /** {@inheritDoc} */
  @Override
  public StringBuilder dump(final int indent, final Set<Object> alreadyDumped) {
    final StringBuilder sb = super.dump(indent, alreadyDumped);
    alreadyDumped.add(this);
    sb.append(' ').append(label);
    return sb;
  }
}
