FizzBuzz from the (fun (with Scheme)) open space at CodeMash

fizzbuzz.scm

;; FizzBuzz

(define-macro (expect . args)
  (if (= 2 (length args))
    (let ((message (car args))
    (test-expression (cadr args)))
      `(if (not ,test-expression)
	 (raise ,message)))
    `(if (not ,(car args))
       (raise ',(car args)))))

(define (output-for number)
  (define (divisible-by? divisor)
    (= 0 (modulo number divisor)))

  (define (fizzy?)
    (divisible-by? 3))
  (define (buzzy?)
    (divisible-by? 5))
  (define (meh?)
    (and (not (fizzy?))
	 (not (buzzy?))))

  (define (string-if condition string)
    (if (condition)
      string
      ""))

  (string-append
    (string-if fizzy? "Fizz")
    (string-if buzzy? "Buzz")
    (string-if meh? (number->string number))))

(expect (string=? "1" (output-for 1)))
(expect (string=? "2" (output-for 2)))
(expect (string=? "Fizz" (output-for 3)))
(expect (string=? "4" (output-for 4)))
(expect (string=? "Buzz" (output-for 5)))
(expect (string=? "Fizz" (output-for 6)))
(expect (string=? "Buzz" (output-for 10)))
(expect (string=? "FizzBuzz" (output-for 15)))

(let fizzbuzzer ((number 1))
  (if (> number 100)
    #f
    (begin
      (display (output-for number))
      (newline)
      (fizzbuzzer (+ 1 number)))))