code: func ProcessWord(word string, env []string) (string, error) {
  	sw := &shellWord{
  		word: word,
  		envs: env,
  		pos:  0,
  	}
  	sw.scanner.Init(strings.NewReader(word))
  	word, _, err := sw.process()
  	return word, err
  }
docs: // ProcessWord will use the 'env' list of environment variables,
  // and replace any env var references in 'word'.