Question

I’m resolving a 4Clojure exercise, this exercise asks you to build your own interpose function. My answer follows:

(fn my-interpose 
  ([separator input] (my-interpose separator input nil))
  ([separator input result] 
    (if 
      (empty? input) 
      (reverse (rest result))
      (my-interpose separator (rest input) (cons separator (cons (first input) result))))))

I’m doing these exercises to learn the language as I read a Clojure book. I will like to know the opinion about my code of people with an experience in the language. Could I avoid the reverse call? Are there any conventions I’m breaking hardly with this kind of code?

Answer 1

What you have is a good proper starting point :). Excellent work.

Starting with what you have you may want to:

• Replace your recursive call with a call to recur because as written it will hit a stack overflow

  (defn foo [stuff]
    (dostuff ... )
    (foo (rest stuff)))
  

  becomes:

  (defn foo [stuff]
    (dostuff ...)
    (recur (rest stuff)))
  

  to avoid blowing the stack. this then often becomes:

  (map dostuff stuff)

• Replace the recustion entirely with the for function

  (for [a one-list b another-list]
    (dont-give-away-the-answer))