Where to stop in the extensibility ladder

Here's a snippet where I explored different places where to "stop" on the ladder of extensibility/abstraction/suggestivity. It's at a very small scale, but those things add up.

Code is in clojure, which makes it even easier to mix and match approaches, because symbols and sets are functions (Like K, where list access and function application looks the same) 

	;; plain feature as string. filter by 1 feature
	(defn- filter-plans
	"Return list of aliases of active plans that have `feature`"
	[feature]
	(->> (products)
	vals
	(mapcat :plans)
	(filter :active)
	(filter #(= feature (:hosting-features %)))
	(map :alias)
	(map keyword)))
	;; maybe more than one? get a list and convert to a set
	(defn- filter-plans
	"Return list of aliases of active plans that have `feature`"
	[features]
	(->> (products)
	vals
	(mapcat :plans)
	(filter :active)
	(filter #(some (set features) (:hosting-features %)))
	(map :alias)
	(map keyword)))
	;; why not getting the full predicate to `some`?
	(defn- filter-plans
	"Return list of aliases of active plans that have `feature`"
	[pred]
	(->> (products)
	vals
	(mapcat :plans)
	(filter :active)
	(filter #(some pred (:hosting-features %)))
	(map :alias)
	(map keyword)))
	;; why not getting the full predicate, passing hosting features?
	(defn- filter-plans
	"Return list of aliases of active plans that have `feature`"
	[pred]
	(->> (products)
	vals
	(mapcat :plans)
	(filter :active)
	(filter #(pred (:hosting-features %)))
	(map :alias)
	(map keyword)))
	;; and, why not the full full filter?
	(defn- filter-plans
	"Return list of aliases of active plans that have `feature`"
	[pred]
	(->> (products)
	vals
	(mapcat :plans)
	(filter :active)
	(filter pred)
	(map :alias)
	(map keyword)))
	;; wait for it....
	(defn- filter-plans
	"Return list of aliases of active plans that have `feature`"
	[pred]
	(->> (products)
	vals
	(mapcat :plans)
	(filter :active)
	pred
	(map :alias)
	(map keyword)))

view raw product_info.clj hosted with ❤ by GitHub