code: func pathParams(r *design.RouteDefinition) string {
  	pnames := r.Params()
  	params := make(design.Object, len(pnames))
  	for _, p := range pnames {
  		params[p] = r.Parent.Params.Type.ToObject()[p]
  	}
  	return join(&design.AttributeDefinition{Type: params}, false, pnames)
  }
docs: // pathParams return the function signature of the path factory function for the given route.