Private def in clojure/clojurescript

Question

In Clojure and clojurescript you can have a private version of defn called defn-, but how do you do the same for def, as def- doesn't seem to be included?

Answer 1

You have to add the :private true metadata key value pair.

(def ^{:private true} some-var :value)
;; or
(def ^:private some-var :value)

The second form is just a short-hand for the first one.

Answer 2

It's worth mentioning, that currently it's not possible to have a private def (and defn) in ClojureScript: https://clojurescript.org/about/differences (under "special forms")

Compilation won't fail and but the def will stay accessible.

Answer 3

If you want a def-, here's how to implement it

(defmacro def- [item value]
  `(def ^{:private true} ~item ~value)
)

Answer 4

This google group post has a discussion about this topic. Apparently the request has been considered. According to one of the responses, defn- was deemed to not be a good idea and decided not to perpetuate it with def and others.