public void addRegExp()

in jflex/src/main/java/jflex/core/NFA.java [177:237]
41 lines of code
10 McCabe index (conditional complexity)

  public void addRegExp(int regExpNum) {

    if (Build.DEBUG)
      Out.debug(
          "Adding nfa for regexp " + regExpNum + " :" + Out.NL + regExps.getRegExp(regExpNum));

    IntPair nfa = insertNFA(regExps.getRegExp(regExpNum));

    List<Integer> lexStates = regExps.getStates(regExpNum);

    if (lexStates.isEmpty()) lexStates = scanner.states.getInclusiveStates();

    for (Integer stateNum : lexStates) {
      if (!regExps.isBOL(regExpNum)) addEpsilonTransition(2 * stateNum, nfa.start());

      addEpsilonTransition(2 * stateNum + 1, nfa.start());
    }

    if (regExps.getLookAhead(regExpNum) != null) {
      Action a = regExps.getAction(regExpNum);

      if (a != null && a.lookAhead() == Action.Kind.FINITE_CHOICE) {
        insertLookAheadChoices(nfa.end(), a, regExps.getLookAhead(regExpNum));
        // remove the original action from the collection: it will never
        // be matched directly, only its copies will.
        scanner.actions.remove(a);
      } else {
        RegExp r1 = regExps.getRegExp(regExpNum);
        RegExp r2 = regExps.getLookAhead(regExpNum);

        IntPair look = insertNFA(r2);

        addEpsilonTransition(nfa.end(), look.start());

        action[look.end()] = a;
        isFinal[look.end()] = true;

        if (a != null && a.lookAhead() == Action.Kind.GENERAL_LOOK) {
          // base forward pass
          IntPair forward = insertNFA(r1);
          // lookahead backward pass
          IntPair backward = insertNFA(r2.rev());

          isFinal[forward.end()] = true;
          action[forward.end()] = new Action(Action.Kind.FORWARD_ACTION);

          isFinal[backward.end()] = true;
          action[backward.end()] = new Action(Action.Kind.BACKWARD_ACTION);

          int entry = 2 * (regExps.getLookEntry(regExpNum) + numLexStates);
          addEpsilonTransition(entry, forward.start());
          addEpsilonTransition(entry + 1, backward.start());

          a.setEntryState(entry);
        }
      }
    } else {
      action[nfa.end()] = regExps.getAction(regExpNum);
      isFinal[nfa.end()] = true;
    }
  }