HELP! Scheme!

So, I recently read about the collatz conjecture on xkcd.
Of course I had read my SICP that day (like every day), so I was
certain, I could easily implement it in Scheme. Like this:

(define (collatz n)
  ((display n)
   (newline)
   (if (> n 1)
       (if (odd? n) (collatz (+ (* 3 n) 1))
           (collatz (/ n 2)))
       1)))

When i call (collatz 10), for instance, PLT Scheme gives
me all the numbers, until it throws an error when it reaches 1:
procedure application: expected procedure, given: #<void>; arguments were: #<void> 1

How do I do it right?

>>1
My Scheme is a bit rusty, butI think you need to wrap your  main body forms in a begin, like this:
(begin (display n) ...), or even simpler, if you were using paredit, go over the first paren and press M-s to split it:

(define (collatz n)
  (display n) (newline)
  (if (> n 1)
      (if (odd? n) (collatz (+ (* 3 n) 1))
          (collatz (/ n 2)))
      1))
I tested it and it works just fine.

>>1
You haven't read your SICP everyday.
display always evaluates to undefined and then you're applying it as a function.

>>3
...to yet another undefined and then the last argument won't evaluate anyway because you're throwing up issues with application to an undefined value everywhere.

>>4
I compared my solution with >>2 and it looks like I put the body of collatz in parentheses, and that was all.
Just a typo. Now it works.

...do you even know what parentheses denote in SICP Scheme outside from special forms?

>>6
Ocular trauma.

>>7
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