Clojure language 10: FN object

(FN...) can be used to create anonymous functions, such:

User => (FN [x] (+ 2 X) # <user $ eval328 $ FN _ 329 user $ eval328 $ FN _ 329 @ f41393>

Accept a parameter X and add 2. The above call defines a function using FN, but it is not executed. If you want to execute it immediately, you can add brackets and parameters:

User => (FN [x] (+ 2 X) 5) 7

But in more cases, we want to define the function first and use it repeatedly. You can combine the following Def:

User => (def f (FN [x] (+ 2 X) # 'user/Fuser => (F 1) 3 user => (F 6) 8

In this way, the F function is defined and then called twice.

FN also supports variable parameter overloading, and actually implements the FN interface. For more information, see the official documentation:

Http://clojure.org/special_forms#fn