code: func (x *Generator) Add(p string) error {
  	if x.fsFilesMap == nil {
  		x.fsFilesMap = make(map[string]file)
  	}
  
  	if x.fsDirsMap == nil {
  		x.fsDirsMap = make(map[string][]string)
  	}
  
  	p = path.Clean(p)
  
  	info, err := os.Stat(p)
  
  	if err != nil {
  		return err
  	}
  
  	prefix, p := x.splitRelPrefix(p)
  
  	if err := x.addParents(p, prefix); err != nil {
  		return err
  	}
  
  	return x.addPath(path.Dir(p), prefix, info)
  }
docs: // Add a file or directory asset to the generator. Added directories will be
  // recursed automatically.