@Override
 public Handle range(GrammarAST a, GrammarAST b) {
   ATNState left = newState(a);
   ATNState right = newState(b);
   int t1 = CharSupport.getCharValueFromGrammarCharLiteral(a.getText());
   int t2 = CharSupport.getCharValueFromGrammarCharLiteral(b.getText());
   left.addTransition(new RangeTransition(right, t1, t2));
   a.atnState = left;
   b.atnState = left;
   return new Handle(left, right);
 }
 protected int getTokenType(@NotNull GrammarAST atom) {
   int ttype;
   if (g.isLexer()) {
     ttype = CharSupport.getCharValueFromGrammarCharLiteral(atom.getText());
   } else {
     ttype = g.getTokenType(atom.getText());
   }
   return ttype;
 }
  @Override
  public Handle set(GrammarAST associatedAST, List<GrammarAST> alts, boolean invert) {
    ATNState left = newState(associatedAST);
    ATNState right = newState(associatedAST);
    IntervalSet set = new IntervalSet();
    for (GrammarAST t : alts) {
      if (t.getType() == ANTLRParser.RANGE) {
        int a = CharSupport.getCharValueFromGrammarCharLiteral(t.getChild(0).getText());
        int b = CharSupport.getCharValueFromGrammarCharLiteral(t.getChild(1).getText());
        set.add(a, b);
      } else if (t.getType() == ANTLRParser.LEXER_CHAR_SET) {
        set.addAll(getSetFromCharSetLiteral(t));
      } else if (t.getType() == ANTLRParser.STRING_LITERAL) {
        int c = CharSupport.getCharValueFromGrammarCharLiteral(t.getText());
        if (c != -1) {
          set.add(c);
        } else {
          g.tool.errMgr.grammarError(
              ErrorType.INVALID_LITERAL_IN_LEXER_SET, g.fileName, t.getToken(), t.getText());
        }
      } else if (t.getType() == ANTLRParser.TOKEN_REF) {
        g.tool.errMgr.grammarError(
            ErrorType.UNSUPPORTED_REFERENCE_IN_LEXER_SET, g.fileName, t.getToken(), t.getText());
      }
    }
    if (invert) {
      left.addTransition(new NotSetTransition(right, set));
    } else {
      Transition transition;
      if (set.getIntervals().size() == 1) {
        Interval interval = set.getIntervals().get(0);
        transition = new RangeTransition(right, interval.a, interval.b);
      } else {
        transition = new SetTransition(right, set);
      }

      left.addTransition(transition);
    }
    associatedAST.atnState = left;
    return new Handle(left, right);
  }