code: func (i *ignore) Absolute(path string, isdir bool) Match {
  	// does the file share the same directory as this ignore file?
  	if !strings.HasPrefix(path, i._base) {
  		return nil
  	}
  
  	// extract the relative path of this file
  	_prefix := len(i._base) + 1
  	_rel := string(path[_prefix:])
  	return i.Relative(_rel, isdir)
  }
docs: // Absolute attempts to match an absolute path against this GitIgnore. If
  // the path is not located under the base directory of this GitIgnore, or
  // is not matched by this GitIgnore, nil is returned.