ycomb.scm

Y-combinator 解决fibonacci数列的一个实现

(define fact-maker
  (lambda(proc)
    (lambda(n)
      (if (= n 0)
          1
          (* n ((proc proc) (- n 1)))))))
(define fact
  ((lambda(proc)
     (lambda(n) 
       (if (= n 0)
           1
           (* n ((proc proc) (- n 1))))))
   (lambda (proc)
     (lambda (n)
       (if (= n 0)
           1 
           (* n ((proc proc) (- n 1))))))))

(define Y
  (lambda(X)
    ((lambda(proc)
       (X (lambda(arg) ((proc proc) arg))))
     (lambda(proc)
       (X (lambda(arg) ((proc proc) arg)))))))


(define fib
  (lambda(proc)
    (lambda(n)
      (if (zero? n)
          1
          (* n (proc (- n 1)))))))
(define Y
  (lambda (P)
    (let ((power-gen (lambda (self)
                       (P (lambda(arg) ((self self) arg))))))
      (power-gen power-gen))))

;test findmax
(define (findmax l)
  (if (null? l)
      'non-list
      (if (null? (cdr l))
          (car l)
          (max (car l) (findmax (cdr l))))))
(define fm
  (lambda (proc)
    (lambda (l)
      (if (null? l)
          'non
          (if (null? (cdr l))
              (car l)
              (max (car l) (proc (cdr l))))))))