diff options
Diffstat (limited to 'sem7/pp/lec3.scm')
| -rw-r--r-- | sem7/pp/lec3.scm | 106 |
1 files changed, 53 insertions, 53 deletions
diff --git a/sem7/pp/lec3.scm b/sem7/pp/lec3.scm index 42b30e1..3e6dbfe 100644 --- a/sem7/pp/lec3.scm +++ b/sem7/pp/lec3.scm @@ -1,20 +1,20 @@ (define (to-string thing) (let ([format-pair-tail - (lambda (tail) - (apply string-append (cond [(null? tail) (list "")] - [(pair? tail) (list " " (to-string tail))] - [else (list " . " (to-string tail))]))) - ]) + (lambda (tail) + (apply string-append (cond [(null? tail) (list "")] + [(pair? tail) (list " " (to-string tail))] + [else (list " . " (to-string tail))]))) + ]) (cond [(number? thing) (number->string thing)] - [(symbol? thing) (symbol->string thing)] - [(null? thing) "()"] - [(procedure? thing) "#function#"] - [(pair? thing) (string-append - (to-string (car thing)) - (format-pair-tail (cdr thing)))] - [(string? thing) thing] - [else "?"] - ))) + [(symbol? thing) (symbol->string thing)] + [(null? thing) "()"] + [(procedure? thing) "#function#"] + [(pair? thing) (string-append + (to-string (car thing)) + (format-pair-tail (cdr thing)))] + [(string? thing) thing] + [else "?"] + ))) (define (send obj msg . para) (let ((method (obj obj msg))) @@ -28,34 +28,34 @@ (let ([whoami 'object]) (lambda (self msg) (cond [(eq? msg 'pretty-str) (lambda () (to-string (send self 'pretty)))] - [(eq? msg 'pretty) (lambda () (list whoami))] - [(eq? msg 'type-of) (lambda () whoami)] - [(eq? msg 'class-of) (lambda () object)] - [else (errorf object "msg ~a not found" msg)]) + [(eq? msg 'pretty) (lambda () (list whoami))] + [(eq? msg 'type-of) (lambda () whoami)] + [(eq? msg 'class-of) (lambda () object)] + [else (errorf object "msg ~a not found" msg)]) ))) (define (point x y) (let ([whoami 'point] - [super (object)]) + [super (object)]) (lambda (self msg) (cond [(eq? msg 'getx) (lambda () x)] - [(eq? msg 'gety) (lambda () y)] - [(eq? msg 'add) (lambda (other) - (new-instance (send self 'class-of) - (+ x (send other 'getx)) - (+ y (send other 'gety)) - ))] - [(eq? msg 'pretty) (lambda () (list whoami x y))] - [(eq? msg 'move) (lambda (dx dy) - (send self 'add (new-instance point dx dy)))] - [(eq? msg 'type-of) (lambda () whoami)] - [(eq? msg 'class-of) (lambda () point)] - [(eq? msg 'with-color) (lambda (color) - (new-instance color-point - (send self 'getx) - (send self 'gety) - color))] - [else (super self msg)])) + [(eq? msg 'gety) (lambda () y)] + [(eq? msg 'add) (lambda (other) + (new-instance (send self 'class-of) + (+ x (send other 'getx)) + (+ y (send other 'gety)) + ))] + [(eq? msg 'pretty) (lambda () (list whoami x y))] + [(eq? msg 'move) (lambda (dx dy) + (send self 'add (new-instance point dx dy)))] + [(eq? msg 'type-of) (lambda () whoami)] + [(eq? msg 'class-of) (lambda () point)] + [(eq? msg 'with-color) (lambda (color) + (new-instance color-point + (send self 'getx) + (send self 'gety) + color))] + [else (super self msg)])) )) @@ -64,18 +64,18 @@ (define (color-point x y . color) (let ([color (if (null? color) 'green (car color))] - [whoami 'color-point] - [super (point x y)]) + [whoami 'color-point] + [super (point x y)]) (lambda (self msg) (cond [(eq? msg 'get-color) (lambda () color)] - [(eq? msg 'type-of) (lambda () whoami)] - [(eq? msg 'pretty) (lambda () - (list whoami - (send self 'getx) - (send self 'gety) - (send self 'get-color)))] - [(eq? msg 'class-of) (lambda () color-point)] - [else (super self msg)])) + [(eq? msg 'type-of) (lambda () whoami)] + [(eq? msg 'pretty) (lambda () + (list whoami + (send self 'getx) + (send self 'gety) + (send self 'get-color)))] + [(eq? msg 'class-of) (lambda () color-point)] + [else (super self msg)])) )) ;;# Exercise 3.7 @@ -85,10 +85,10 @@ (z 3) (v 5)) (cons x - (call/cc (lambda (e) - (cons y - (cons z - (if (even? v) v (e (+ v 1))))))))) + (call/cc (lambda (e) + (cons y + (cons z + (if (even? v) v (e (+ v 1))))))))) ;; Okay lets start by looking at it: ;; Okay, we define x y z and v ;; Then we create a cons with x and the continuations, so the result must be @@ -107,8 +107,8 @@ (k (* a b))) (define (dist a b c k) (mult a c (lambda (v) - (mult 4 v (lambda (v1) - (mult b b (lambda (v2) - (sub v2 v1 k)))))))) + (mult 4 v (lambda (v1) + (mult b b (lambda (v2) + (sub v2 v1 k)))))))) (define dist-old (lambda (a b c) (- (* b b) (* 4 a c)))) |