Little Clojure tip: name sets as if they are predicates (where appropriate).

In Clojure it's quite common to use sets as functions (it acts as a function that tests membership).

(some #{a} coll)
(filter (comp #{1 2 3} :id) coll)

This is idiomatic, if you've done a bit of Clojure you will read this easily, because they are set literals it's quite obvious. But if the set is defined somewhere else, then suddenly it gets a lot less obvious.

(def admin-ids #{53 65 78})

(when (admin-ids (:id user)) ,,,)

In this case I would probably use an explicit contains?, at least that shows that it has to be a set or map.

(when (contains? admin-ids (:id user)) ,,,)

But you can also name the var as if it's a function

(def admin-id? #{53 65 78})
(when (admin-id? (:id user)) ,,,)

And this way you could refactor this later to actually be a function, e.g. something that checks the database.

#clojure