code: func SearchHelp() string {
  	type help struct{ Name, Description string }
  	h := []help{}
  	for _, p := range keywords {
  		h = append(h, help{p.Name(), p.Description()})
  	}
  	b, err := json.MarshalIndent(h, "", "  ")
  	if err != nil {
  		return "Error marshalling"
  	}
  	return string(b)
  }
docs: // SearchHelp returns JSON of an array of predicate names and descriptions.