CODEWITHSUNDEEP
functional-programminglispclojure
Jeroko
Jeroko

Reputation: 313

- Clojure - I get an error when I run this fibonacci function, any idea what's wrong?

I picked up clojure a few hours ago and am trying to get a Fibonacci function working

Here is the function I'm defining

(defn fib [x]
  (if (or (= x 1) (= x 2))
    ((inc 0))
      ((+ (fib (- x 1)) (fib (- x 2))))

))

and I get this error: java.lang.Long cannot be cast to clojure.lang.IFn user/fib (NO_SOURCE_FILE:3)

Though I'm unfamiliar with almost all the language constructs this seems to be correct as far as I know. Any idea what's wrong?

Upvotes: 0

Views: 38

Answers (1)

daniel gratzer
daniel gratzer

Reputation: 53881

You've made the classic mistake of too many parens, in Lisps, parens mean "apply this function" so it's important to only put them around functions:

(defn fib [x]
  (if (or (= x 1) (= x 2))
      1
      (+ (fib (- x 1))
         (fib (- x 2)))))

Your error essentially means "Hey, you just tried to apply a number!" so we need to remove the redundant parens.

Upvotes: 5

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