ovidiu 02/01/25 15:04:07
Added: src/scratchpad/schecoon/scheme utils.scm
Log:
Auxiliary functions.
Revision Changes Path
1.1 xml-cocoon2/src/scratchpad/schecoon/scheme/utils.scm
Index: utils.scm
===================================================================
;; utils.scm
;;
;; Auxiliary functions.
;;
;; Author: Ovidiu Predescu <[EMAIL PROTECTED]>
;; Date: January 24, 2002
;;
;; Filter a list through a predicate; only those elements of the list
;; for whom the predicate is true are returned in resulting list.
(define (filter pred lst)
(define (filter-helper lst acc)
(cond ((null? lst) acc)
(else
(let ((elem (car lst)))
(if (pred elem)
(filter-helper (cdr lst) (cons elem acc))
(filter-helper (cdr lst) acc))))))
(reverse (filter-helper lst '())))
;; Handy shortcut for a C printf() like function. Use ~s instead of %s
;; and ~% instead of \n.
(define (printf . args)
(display (apply format args)))
;; Remove the extra paranthesis within a list. E.g.
;; (flatten '(1 2 (a b (c d)) 3 4)) -> (1 2 a b c d 3 4)
(define (flatten lst)
(define (flatten-helper lst acc)
(if (null? lst)
acc
(let ((elem (car lst)))
(if (pair? elem)
(flatten-helper (cdr lst) (append (flatten-helper elem '()) acc))
(flatten-helper (cdr lst) (cons elem acc))))))
(reverse (flatten-helper lst '())))
----------------------------------------------------------------------
In case of troubles, e-mail: [EMAIL PROTECTED]
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
