;; file:  hw1pr1.rkt
;; submission site id:
;; time spent:
;; other comments?

#lang racket
(require htdp/testing)

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;; Function 0
;;   one possible example of appropriate commenting
;;   and testing...
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;; len
;;  inputs: L, a list of any items
;;  output: the number of top-level items in the input list
(define (len L)
  (if (null? L)
      0
      (+ 1 (len (rest L)))))

; provided tests
(check-expect (len '())  0)           
(check-expect (len '(s p a m))  4)    

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Function 1
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;; remove-all
;;  inputs: 
;;  output: 
(define (remove-all e L)
  0) ;; empty until implemented!

; provided tests
(check-expect (remove-all "i" '("a" "l" "i" "i" "i" "e" "n")) 
              '("a" "l" "e" "n"))
(check-expect (remove-all "i" '( ("a" "l" "i") "i" "i" "e" "n")) 
              '(("a" "l" "i") "e" "n"))
(check-expect (remove-all 0 '(1 0 1 0 1 0))  
              '(1 1 1))

; additional tests

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;; Function 2
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;; prefix 
;;  inputs: 
;;  output: 
(define (prefix? P L)
  0)

; provided tests
(check-expect (prefix? '() '(s p a m))   #t)
(check-expect (prefix? '(s p) '(s p a m))   #t)
(check-expect (prefix? '(s m) '(s p a m))   #f)
(check-expect (prefix? '(p a) '(s p a m))   #f)

; additional tests

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Function 3
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;; sublist
;;  inputs: 
;;  output: 
(define (sublist? S L)
  0)

; provided tests
(check-expect (sublist? '() '(s p a m))   #t)
(check-expect (sublist? '(s p) '(s p a m))   #t)
(check-expect (sublist? '(s m) '(s p a m))   #f)
(check-expect (sublist? '(p a) '(s p a m))   #t)
(check-expect (sublist? '(a b c) '(b a b a c))  #f)
(check-expect (sublist? '(a b c) '(b a b c c))  #t)

; additional tests

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Function 4
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;; enumerate
;;  inputs: 
;;  output: 
(define (enumerate L)
  0)

; provided tests
(check-expect (enumerate '(jan feb mar apr)) 
              '((0 jan) (1 feb) (2 mar) (3 apr)))
(check-expect (enumerate '(0 I II III IV V VI)) 
              '((0 0) (1 I) (2 II) (3 III) (4 IV) (5 V) (6 VI)))
(check-expect (enumerate '())  
              '())

; additional tests

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(generate-report)