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      fn?

      clojure.core

      Available since 1.0 (source)
      • (fn? x)
      Returns true if x implements Fn, i.e. is an object created via fn.
      © Rich Hickey. All rights reserved. Eclipse Public License 1.0
      2 Examples
      user=> (fn? 5)
false
user=> (fn? inc)
true
user=> (fn? (fn []))
true
user=> (fn? #(5))
true
      ;; Even though maps, sets, vectors and keywords behave as functions:
user=> ({:a 1} :a)
1

;; fn? still returns false for them because they are not created using fn:
user=> (fn? {:a 1})
false
      See Also
      clojure.core/ifn?

      Returns true if x implements IFn. Note that many data structures (e.g. sets and maps) implement IF...

      Added by mmwaikar
      1 Note
        By , created 7.6 years ago

        Note fn? only tests if something was created using fn, not if it’s a function. Use ifn? for that. Some things are functions even though they weren’t created with fn, such as maps, vectors and keywords.