Two options. The first, straightforward one: make the thing that's implementing the protocol the Storage, not in the individual things being stored. So something like:
(defprotocol ItemStore (save-item [store item]) (load-items [store items])) etc. Second option: Clojure has multimethods too, though (as I understand them), they aren't as powerful or free-form. Combined with marker protocols though, you can probably put together something that works. ;; Marker protocol, doesn't have any methods attached to it (defprotocol Loadable) (defrecord LoadableThing [my-data] Loadable) ;; Let Clojure knows that it satisfies the protocol ;; Define a dispatch function that can figure out which multimethod to call. (defn loadable-dispatch [item] (cond (satisfies? LoadableThing item) :load-single On Sunday, August 28, 2016 at 7:29:46 AM UTC-7, Jonathon McKitrick wrote: > > I'm beginning a foray into protocols after coming from the Common Lisp > world of multimethods. I'm using them initially to implement a consistent > load/save API over the DB layer. > > It's pretty simple to have a Saveable protocol to save one object, because > the first argument is a Record of the type I am saving. > > But since protocols dispatch on the first argument, how do you define a > Loadable protocol that loads an object or handles a collection of objects? > > For example, if I want to load an object by idx, the first argument is not > a Record, but an integer, or perhaps an arbitrary field to used in a query. > > > -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
