int readEscapeSequence()

in lib/src/tokenizer_base.dart [366:413]
43 lines of code
15 McCabe index (conditional complexity)

  int readEscapeSequence() {
    final ch = _nextChar();
    int hexValue;
    switch (ch) {
      case 110 /*n*/ :
        return TokenChar.NEWLINE;
      case 114 /*r*/ :
        return TokenChar.RETURN;
      case 102 /*f*/ :
        return TokenChar.FF;
      case 98 /*b*/ :
        return TokenChar.BACKSPACE;
      case 116 /*t*/ :
        return TokenChar.TAB;
      case 118 /*v*/ :
        return TokenChar.FF;
      case 120 /*x*/ :
        hexValue = readHex(2);
        break;
      case 117 /*u*/ :
        if (_maybeEatChar(TokenChar.LBRACE)) {
          hexValue = readHex();
          if (!_maybeEatChar(TokenChar.RBRACE)) {
            return -1;
          }
        } else {
          hexValue = readHex(4);
        }
        break;
      default:
        return ch;
    }

    if (hexValue == -1) return -1;

    // According to the Unicode standard the high and low surrogate halves
    // used by UTF-16 (U+D800 through U+DFFF) and values above U+10FFFF
    // are not legal Unicode values.
    if (hexValue < 0xD800 || hexValue > 0xDFFF && hexValue <= 0xFFFF) {
      return hexValue;
    } else if (hexValue <= 0x10FFFF) {
      messages.error('unicode values greater than 2 bytes not implemented yet',
          _file.span(_startIndex, _startIndex + 1));
      return -1;
    } else {
      return -1;
    }
  }