code: func IsFilePath(str string) (bool, int) {
  	if rxWinPath.MatchString(str) {
  		//check windows path limit see:
  		//  http://msdn.microsoft.com/en-us/library/aa365247(VS.85).aspx#maxpath
  		if len(str[3:]) > 32767 {
  			return false, Win
  		}
  		return true, Win
  	} else if rxUnixPath.MatchString(str) {
  		return true, Unix
  	}
  	return false, Unknown
  }
docs: // IsFilePath check is a string is Win or Unix file path and returns it's type.