An alternative approach is to have a keyword argument named method, then users can write #:method (data-method ...) or #:method (form-method ...) or #:method (json-method ...). It’s more extensible and mutually exclusive by construction.

(method is just a random word that came to my mind. There might be a better word)

Method isn’t a great name here, since it means get/put/etc in this context

But also the current design is somewhat more convenient