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Copy pathLaboration 2 kompletteringinlämning.scm
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Laboration 2 kompletteringinlämning.scm
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(load "music-db.scm")
(load "quicksort-skel.scm")
(require (lib "trace.ss"))
;Problem 1
(define (atom? n)
(if
(or (null? n) (pair? n) )
#f
#t))
;Problem 2
(define (count-list lst)
(if (null? lst)
0
(+ 1 (count-list(cdr lst)))))
;Problem 3
(define (keep-if pred lat)
(cond
((null? lat) '())
((pred (car lat))
(cons (car lat) (keep-if pred (cdr lat))))
(else (keep-if pred (cdr lat)))))
;Problem 4
(define (first-n numb-of-ele lst)
(cond
((= numb-of-ele 0)'())
((null? lst) '())
(else (cons (car lst) (first-n (- numb-of-ele 1) (cdr lst))))))
;Problem 5
(define (range from to step)
(if (> from to)
'()
(cons from (range (+ from step) to step))))
;Problem 6
;Iterative
(define (reverse-order lst)
(define (reverse-iter lst res)
(if (null? lst)
res
(reverse-iter (cdr lst) (cons (car lst) res))))
(reverse-iter lst '()))
;Linear Recursive
(define (reverse-order-2 lst)
(if (null? lst)
lst
(my-append (reverse-order-2 (cdr lst)) (cons (car lst) ()))))
(define (my-append lst1 lst2)
(if (null? lst1)
lst2
(cons (car lst1) (my-append (cdr lst1) lst2))))
;Problem 7
(define (map-to-each funktion lst)
(if (null? lst)
'()
(cons (funktion (car lst)) (map-to-each funktion (cdr lst)))))
;Problem 8
(define (count-all lst)
(cond
((null? lst) 0)
((list? (car lst)) (+ (count-all (car lst)) (count-all (cdr lst))))
(else (+ 1 (count-all(cdr lst))))))
(define (keep-if-all pred lst)
(cond
((null? lst) '())
((list? (car lst)) (cons (keep-if-all pred (car lst)) (keep-if-all pred (cdr lst))))
((pred (car lst)) (cons (car lst) (keep-if-all pred (cdr lst))))
(else (keep-if-all pred (cdr lst)))))
;Problem 9
(define (list-equal? lst1 lst2)
(cond
((and (null? lst1) (not (null? lst2))) #f)
((and (null? lst2) (not (null? lst1))) #f)
((and (null? lst1) (null? lst2)) #t)
((and (atom? lst1) (atom? lst2)) (eq? lst1 lst2))
((and (and (atom? (car lst1)) (atom? (car lst2))) (eq? (car lst1) (car lst2)))(list-equal? (cdr lst1) (cdr lst2)))
((eq? (car lst1) (car lst2)) (list-equal1? (cdr lst1) (cdr lst2)))
((and (list? (car lst1)) (list? (car lst2))) (and (list-equal? (car lst1) (car lst2)) (list-equal? (cdr lst1) (cdr lst2))))
(else #f)))
;Problem 10
(define (occurs*? val lst)
(cond
((null? lst) #f)
((atom? lst) (eq? val lst))
(else (or
(occurs*? val (car lst))
(occurs*? val (cdr lst))))))
;Problem 11
(define (subst-all gammal ny lst)
(cond
((null? lst) '())
((list? (car lst)) (cons (subst-all gammal ny (car lst)) (subst-all gammal ny (cdr lst))))
((eq? gammal (car lst)) (cons ny (subst-all gammal ny (cdr lst))))
(else (cons (car lst) (subst-all gammal ny (cdr lst))))))
;Problem 12
(define (partition pivot lon)
(define (phelper pivot lon less-or-equal greater)
(cond
((null? lon) (cons less-or-equal greater))
(( <= (car lon) pivot) (phelper pivot (cdr lon) (cons (car lon) less-or-equal) greater))
(else (phelper pivot (cdr lon) less-or-equal (cons (car lon) greater)))))
(phelper pivot lon '() '()))
;Problem 13
;(define (get-first-record lst)
; (car lst))
;(define (get-rest-records lst)
; (cdr lst))
;(define (get-title lst)
; (car lst))
;(define (get-artist lst)
; (car (cdr lst)))
;
;(define (get-year lst)
; (car (cdr (cdr lst))))
;
;(define (get-genre lst)
; (car (cdr (cdr (cdr lst)))))
;
;(define (*the-empty-database*)
; '())
;
;(define (add-record record database)
; (cons record database))
;
;(define (empty-database? database)
; (eq? database *the-empty-database*))
;
;
;Problem 14
(define (get-all field testcase database)
(if (empty-database? database)
'()
(cond
((eq? field 'title) (if (list-equal? (get-title (get-first-record database)) testcase)
(add-record (get-first-record database) (get-all field testcase (get-rest-records database)))
(get-all field testcase (get-rest-records database))))
((eq? field 'artist) (if (list-equal? (get-artist (get-first-record database)) testcase)
(add-record (get-first-record database) (get-all field testcase (get-rest-records database)))
(get-all field testcase (get-rest-records database))))
((eq? field 'year) (if (eqv? (get-year (get-first-record database)) testcase)
(add-record (get-first-record database) (get-all field testcase (get-rest-records database)))
(get-all field testcase (get-rest-records database))))
((eq? field 'genre) (if (list-equal? (get-genre (get-first-record database)) testcase)
(add-record (get-first-record database) (get-all field testcase (get-rest-records database)))
(get-all field testcase (get-rest-records database)))))))
;Problem 15
(define (get-count field testcase database)
(if (empty-database? database)
0
(cond
((eq? field 'title) (if (list-equal? (get-title (get-first-record database)) testcase)
(+ 1 (get-count field testcase (get-rest-records database)))
(get-all field testcase (get-rest-records database))))
((eq? field 'artist) (if (list-equal? (get-artist (get-first-record database)) testcase)
(+ 1 (get-count field testcase (get-rest-records database)))
(get-all field testcase (get-rest-records database))))
((eq? field 'year) (if (eqv? (get-year (get-first-record database)) testcase)
(+ 1 (get-count field testcase (get-rest-records database)))
(get-count field testcase (get-rest-records database))))
((eq? field 'genre) (if (list-equal? (get-genre (get-first-record database)) testcase)
(+ 1 (get-count field testcase (get-rest-records database)))
(get-all field testcase (get-rest-records database)))))))
(define (count-list lst)
(if (null? lst)
0
(+ 1 (count-list(cdr lst)))))
(define (count-list lst)
(if (null? lst)
0
(+ 1 (count-list(cdr lst)))))
;Problem 16
(define (one-word-entry? entry)
(and (list? entry) (= (count-list entry) 1)))
(define (songs-where field predicate database)
(if (or (eq? field 'title)
(eq? field 'artist)
(eq? field 'year)
(eq? field 'genre))
(if (empty-database? database)
'()
(cond
((eq? field 'title) (if (predicate (get-title (get-first-record database)))
(add-record (get-first-record database) (songs-where field predicate (get-rest-records database)))
(songs-where field predicate (get-rest-records database))))
((eq? field 'artist) (if (predicate (get-artist (get-first-record database)))
(add-record (get-first-record database) (songs-where field predicate (get-rest-records database)))
(songs-whsubst-all gammalere field predicate (get-rest-records database))))
((eq? field 'year) (if (predicate (get-year (get-first-record database)))
(add-record (get-first-record database) (songs-where field predicate (get-rest-records database)))
(songs-where field predicate (get-rest-records database))))
((eq? field 'genre) (if (predicate (get-genre (get-first-record database)))
(add-record (get-first-record database) (songs-where field predicate (get-rest-records database)))
(songs-where field predicate (get-rest-records database))))))
(display "Error: Unknown field")))
;Problem 17
(define (get-first-record lst)
(car lst))
(define (get-rest-records lst)
(cdr lst))
(define (get-title lst)
(if (eq? (car (car (cdr lst))) 'title)
(cdr (car (cdr lst)))
(get-title (cdr lst))))
(define (get-artist lst)
(if (eq? (car (car (cdr lst))) 'artist)
(cdr (car (cdr lst)))
(get-artist (cdr lst))))
(define (get-year lst)
(if (eq? (car (car (cdr lst))) 'year)
(cdr (car (cdr lst)))
(get-year (cdr lst))))
(define (get-genre lst)
(if (eq? (car (car (cdr lst))) 'genre)
(cdr (car (cdr lst)))
(get-genre (cdr lst))))
(define *the-empty-database*
'())
(define (add-record record database)
(list database (subst-all '1 '117 record)))
(define (empty-database? database)
(eq? database *the-empty-database*))