Getting Clojure

A Functional Toolkit

Since so much of Clojure programming revolves around creating, combining, and using functions, it’s unsurprising that the language provides a fair number of functions aimed at easing the job.

Take, for example, the apply function. It tackles the surprisingly common situation where you have a function and the arguments that you want to call that function with in a collection. In other words, instead of having this:

(+ 1 2 3 4)          ; Gives you 10.

what if you had the function (+ in this case) and the arguments, like this:

(def the-function +)
(def args [1 2 3 4])

Enter apply. You supply a function and a collection of arguments, and apply will call that function with the arguments, returning the result. Armed with apply ...