59441
jdrake
<string>First paste in 2 months here!</string>
(define (within? x lower upper)
(and (<= x upper) (>= x lower)))
; rotate-char char amount lower upper -> char
; If char is within lower and upper range, increase char by amount, and if
; it goes over the upper range, then wrap around to the lower range.
(define (rotate-char in amount lower upper)
(let
((in (char->integer in))
(lower (char->integer lower))
(upper (char->integer upper)))
(integer->char
(if (within? in lower upper)
(begin
(set! in (+ in amount))
(if (> in upper)
(+ lower (- in upper) -1)
in))
in))))
(define (rot13 in)
(cond
((char-lower-case? in) (rotate-char in 13 #\a #\z))
((char-upper-case? in) (rotate-char in 13 #\A #\Z))
(else in)))
; I am not sure I want to think about this for now...
;(define (rotate-char2 in amount lower upper)
; (let loop ((i in))
; (cond
; ((< i lower) (loop (+ i amount)))
; ((< i upper) i)
; (else (loop (+ lower (- i upper)))))))
3417743586
#lispcafe
8
offby1
<string>Mister Gorbachov, rewrite "within"</string>
(define (within? x lower upper)
(<= lower x upper))
3417748718
#lispcafe
7
offby1
<string>my scary hairy dense version!! I still prefer it.</string>
(define (rot13-char c)
(cond
((char-alphabetic? c)
(let ((upper? (char-upper-case? c))
(c (char-downcase c)))
((if upper?
char-upcase
values)
(integer->char (+ (char->integer #\a)
(remainder (+ 13 (- (char->integer c)
(char->integer #\a))) 26))))))
(else
c)
))
3417748501
#lispcafe
6
offby1
<string>ports</string>
(define (rot13-stream in out)
(let loop ()
(let ((ch (read-char in)))
(when (not (eof-object? ch))
(display (rot13-char ch) out)
(loop)))))
3417748268
#lispcafe
5
jdrake
<string>Preliminary Final Code: Comments?</string>
#!/usr/bin/env mzscheme
; Special thanks to Vixey in #lispcafe
; within? x lower upper
; Is x is within lower to upper?
(define (within? x lower upper)
(<= lower x upper))
; wrap-range x lower upper
; If x is above range, it will wrap from lower
; If x is below range, it will wrap from upper
; It will repeat if necessary
(define (wrap-range x lower upper)
(cond
((> x upper) (wrap-range (+ lower (- x upper) -1) lower upper))
((< x lower) (wrap-range (- upper (- lower x) -1) lower upper))
(else x)))
; rotate-char char amount lower upper -> char
; If char is within lower and upper range, increase char by amount, and if
; it goes over the upper range, then wrap around to the lower range.
(define (rotate-char x amount lower upper)
(let
((x (char->integer x))
(lower (char->integer lower))
(upper (char->integer upper)))
(integer->char
(if (within? x lower upper)
(wrap-range (+ x amount) lower upper)
x))))
; rot13 x
; Converts char x to its rot13 equivalent
(define (rot13 x)
(cond
((char-lower-case? x) (rotate-char x 13 #\a #\z))
((char-upper-case? in) (rotate-char x 13 #\A #\Z))
(else x)))
; rot13-string string
; Converts a string to its rot13 equivalent
(define (rot13-string string)
(list->string (map rot13 (string->list string))))
3417747266
#lispcafe
4
jdrake
<string>Complete Code</string>
(define (within? x lower upper)
(and (<= x upper) (>= x lower)))
(define (wrap-range x lower upper)
(cond
((> x upper) (wrap-range (+ lower (- x upper)) lower upper))
((< x lower) (wrap-range (- upper (- lower x)) lower upper))
(else x)))
; rotate-char char amount lower upper -> char
; If char is within lower and upper range, increase char by amount, and if
; it goes over the upper range, then wrap around to the lower range.
(define (rotate-char in amount lower upper)
(let
((in (char->integer in))
(lower (char->integer lower))
(upper (char->integer upper)))
(integer->char
(if (within? in lower upper)
(wrap-range (+ in amount) lower upper)
in))))
(define (rot13 in)
(cond
((char-lower-case? in) (rotate-char in 13 #\a #\z))
((char-upper-case? in) (rotate-char in 13 #\A #\Z))
(else in)))
; I am not sure I want to think about this for now...
;(define (rotate-char2 in amount lower upper)
; (let loop ((i in))
; (cond
; ((< i lower) (loop (+ i amount)))
; ((< i upper) i)
; (else (loop (+ lower (- i upper)))))))
3417745436
#lispcafe
3
jdrake
<string>updated rotate-char</string>
(define (rotate-char in amount lower upper)
(let
((in (char->integer in))
(lower (char->integer lower))
(upper (char->integer upper)))
(integer->char
(if (within? in lower upper)
(begin
(set! in (+ in amount))
(wrap-range in lower upper)
in)))))
3417745035
#lispcafe
2
jdrake
<string>New version</string>
(define (wrap-range x lower upper)
(cond
((> x upper) (wrap-range (+ lower (- x upper)) lower upper))
((< x lower) (wrap-range (- upper (- lower x)) lower upper))
(else x)))
3417744710
#lispcafe
1
jdrake
<string>Recurse no worky</string>
(define (wrap-range x lower upper)
(let loop ('())
(cond
((> x upper) (loop (+ lower (- x upper))))
((< x lower) (loop (- upper (- lower x))))
(else x))))
3417744443
#lispcafe