decode escape sequences

        static void escapeDecode(string& sequence) {
            assert(sequence[0] = '\\');
            if(sequence.size() == 2) {
                switch(sequence[1]) {
                case '\'':
                    sequence = '\'';
                    break;
                case '"':
                    sequence = '"';
                    break;
                case '\\':
                    sequence ='\\';
                    break;
                case '0':
                    sequence = '\x00';
                    break;
                case 'n':
                    sequence = '\x0A';
                    break;
                case 'r':
                    sequence = '\x0D';
                    break;
                case 't':
                    sequence = '\x09';
                    break;
                default:
                    break;
                }
            }
            else if(sequence.size() == 4) {
                if(sequence[1] == 'x') {
                    int i;
                    istringstream stream(sequence.substr(2));
                    stream >> std::hex >> i;
                    sequence = i;
                }
                else {
                    int i;
                    istringstream stream(sequence.substr(1));
                    stream >> std::oct >> i;
                    sequence = i;
                }
            }
        }