void String::print(String *str){  char *st= (char*)Ptr, *end= st+str_length;  for (; st < end; st++)  {    uchar c= *st;    switch (c)    {    case '\\':      str->append(STRING_WITH_LEN("\\\\"));      break;    case '\0':      str->append(STRING_WITH_LEN("\\0"));      break;    case '\'':      str->append(STRING_WITH_LEN("\\'"));      break;    case '\n':      str->append(STRING_WITH_LEN("\\n"));      break;    case '\r':      str->append(STRING_WITH_LEN("\\r"));      break;    case '\032': // Ctrl-Z      str->append(STRING_WITH_LEN("\\Z"));      break;    default:      str->append(c);    }  }}