SchemeTraceDefine

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(define indent -1)
(define-macro (trace-define name expr)
 `(define ,name (lambda input
    (set! indent (+ indent 1))
    (print (make-string indent (string-ref "|" 0)) (quote ,name) " " input)

    (let ([f ,expr])
      (let ([r (apply f input)])
        (print (make-string indent (string-ref "|" 0)) r)
        (set! indent (- indent 1))
        r
      )
    )
   )
  )
)

(trace-define fak-rek
  (lambda (n)
    (if (= n 0)
        1
        (* n (fak-rek (- n 1))))))

(trace-define fak-help
  (lambda (n fak)
    (if (= n 0)
        fak
        (fak-help (- n 1) (* n fak)))))

(trace-define fak-it
  (lambda (n)
    (fak-help n 1)))

(fak-rek 5)
(print "------")
(fak-it 5)
(print "------")

SchemeTraceDefine

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