Function isNumericString

src/Common/Utility.cpp:303–312

  }

  bool isNumericString(const std::string& s)
  {
    for (int c : s) {
      if (!isdigit(c)) {
        return false;
      }
    }

    return true;
  }

  int loadFiles(const std::string& directory,
    std::function<std::string(const std::string&, const struct dirent*)> filter,