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Character

case-fold-down-char

(case-fold-down-char ch)

Returns the lowercase form of ch if ch is a member of the uppercase-list list, otherwise returns ch.

(define (case-fold-down-char ch)
  ;; Returns the lowercase form of ch or ch if ch is not an uppercase form
  (let ((idx (list-member-find ch uppercase-list)))
    (if (> idx 0)
	(list-member-get lowercase-list idx)
	ch)))

case-fold-down-charlist

(case-fold-down-charlist charlist)

Returns charlist with all uppercase characters converted to lowercase.

(define (case-fold-down-charlist charlist)
  ;; Shifts all characters in charlist to lowercase
  (if (null? charlist)
      '()
      (cons (case-fold-down-char (car charlist)) 
	    (case-fold-down-charlist (cdr charlist)))))

case-fold-up-char

(case-fold-up-char ch)

Returns the uppercase form of ch if ch is a member of the lowercase-list list, otherwise returns ch.

(define (case-fold-up-char ch)
  ;; Returns the uppercase form of ch or ch if ch is not a lowercase form
  (let ((idx (list-member-find ch lowercase-list)))
    (if (> idx 0)
	(list-member-get uppercase-list idx)
	ch)))

(define uppercase-list
  '(#\A #\B #\C #\D #\E #\F #\G #\H #\I #\J #\K #\L #\M
    #\N #\O #\P #\Q #\R #\S #\T #\U #\V #\W #\X #\Y #\Z))

(define lowercase-list
  '(#\a #\b #\c #\d #\e #\f #\g #\h #\i #\j #\k #\l #\m
    #\n #\o #\p #\q #\r #\s #\t #\u #\v #\w #\x #\y #\z))

case-fold-up-charlist

(case-fold-up-charlist charlist)

Returns charlist with all lowercase characters converted to uppercase.

(define (case-fold-up-charlist charlist)
  ;; Shifts all characters in charlist to uppercase
  (if (null? charlist)
      '()
      (cons (case-fold-up-char (car charlist)) 
	    (case-fold-up-charlist (cdr charlist)))))

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