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guile/ice-9/list.scm
2005-05-23 19:57:22 +00:00

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Scheme

;;;; List functions not provided in R5RS or srfi-1
;;; Copyright (C) 2003 Free Software Foundation, Inc.
;;;
;; This library is free software; you can redistribute it and/or
;; modify it under the terms of the GNU Lesser General Public
;; License as published by the Free Software Foundation; either
;; version 2.1 of the License, or (at your option) any later version.
;;
;; This library is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
;; Lesser General Public License for more details.
;;
;; You should have received a copy of the GNU Lesser General Public
;; License along with this library; if not, write to the Free Software
;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
(define-module (ice-9 list)
:export (rassoc rassv rassq))
(define (generic-rassoc key alist =)
(let loop ((ls alist))
(and (not (null? ls))
(if (= key (cdar ls))
(car ls)
(loop (cdr ls))))))
(define (rassoc key alist . =)
(generic-rassoc key alist (if (null? =) equal? (car =))))
(define (rassv key alist)
(generic-rassoc key alist eqv?))
(define (rassq key alist)
(generic-rassoc key alist eq?))