plp/scheme/scheme2.rkt

#lang racket
(define (minimum L)
  (let ((x (car L))
        (xs (cdr L)))
        (if (null? xs)
            x
            (minimum
             (cons
              (if (< x (car xs))
              x
              (car xs))
              (cdr xs))))))
(minimum '(2 2 1 4 5))

(define (minimum2 x . rest)
  (if (null? rest)
      x
      (apply minimum2
       (cons
        (if (< x (car rest))
            x
            (car rest))
            (cdr rest)))))
(minimum2 5 9 7 88 54 79)

(let ((x 0))
  (let label ()
    (when (< x 10)
      (display x)
      (newline)
      (set! x (+ x 1))
      (label))))

(let label ((x 10))
  (when (> x 0)
    (display x)
    (newline)
    (label (- x 1))))

(define (fact x)
  (define (fact-tail x accum)
    (if (= x 0)
        accum
        (fact-tail (- x 1) (* accum x))))
  (fact-tail x 1))
(fact 10)

(for-each (lambda (x)
            (display x) (newline))
          '(this is it))

(define (vector-for-each body vect)
  (let ((max (- (vector-length vect) 1)))
    (let loop ((i 0))
      (body (vector-ref vect i))
      (when (< i max)
        (loop (+ i 1))))))

(vector-for-each (lambda (x)
                   (display x) (newline))
                 #(this is it))