Introduction to Functional Programming - Part 2

intro_to_fp_2.scm

(if (zero? 0) 4
    (+ "hello" 4.5 '(8 2)))

(define (flatten x)
  (cond ((null? x) '())
        ((list? (car x)) (append (flatten (car x)) (flatten (cdr x))))
        (else (cons (car x) (flatten (cdr x))))))

(flatten '(1 (2 "3") "4" ((5))))

(define (sorted? numbers)
  (or (< (length numbers) 2)
      (and (<= (car numbers) (cadr numbers))
           (sorted? (cdr numbers)))))

(sorted? '(1 3 4 5))

(sorted? '(1 4 5 3))

(sorted? '())

(sorted? '(3.4))

(sorted? '(1/3 4/5 7/2 12/5))

;(sorted? '("Alice" "Bobby" "Carol"))

(define (string-sequence-sorted? strings)
  (or (< (length strings) 2)
      (and (<= (car strings) (cadr strings))
           (string-sequence-sorted? (cdr strings)))))

(string-sequence-sorted? '("Alice" "Bobby" "Carol"))

(define (sorted? sequence comp)
  (or (< (length sequence) 2)
      (and (comp (car sequence) (cadr sequence))
           (sorted? (cdr sequence) comp))))

(sorted? '(1 4 5 7 8 10 14) <)

(sorted? '(8.5 4.3 2.0 0.4 -1.3 -5.5) >)

(sorted? '(8.5 4.3 2.0 0.4 -7.3 -5.5) >)

(sorted? '("apple" "banana" "banana" "cherry") string<=?)

(define (list-length<? ls1 ls2) (< (length ls1) (length ls2)))

(sorted? '((1) ("a" 'b) ((#t) 4.5 (10/3 8+7i))) list-length<?)

(define (my-unary-map fn seq)
  (if (null? seq) '()
      (cons (fn (car seq))
            (my-unary-map fn (cdr seq)))))