case-fold-down-char

DSSSL Library Reference: Part of the Modular DocBook Stylesheet distribution
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case-fold-down-char

Name

case-fold-down-char -- Return the lowercase form of a single character

Synopsis

(case-fold-down-char ch #!optional (uc-list default-uppercase-list)         (lc-list default-lowercase-list))

Description

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

The implied mapping from uppercase to lowercase in the two lists is one-to-one. The first element of the uppercase list is the uppercase form of the first element of the lowercase list, and vice versa.

ch: The character to fold down.
uc-list: The list of uppercase letters. The default is the list of English uppercase letters.
lc-list: The list of lowercase letters. The default is the list of English lowercase letters.

Author

Norman Walsh, <ndw@nwalsh.com>

Source Code

(define (case-fold-down-char ch #!optional (uc-list default-uppercase-list)
					   (lc-list default-lowercase-list))
  ;; Return the lowercase form of a single character
  (let ((idx (list-member-find ch uc-list)))
    (if (>= idx 0)
	(list-ref lc-list idx)
	ch)))

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