guile/module/ice-9/list.scm

;;;; List functions not provided in R5RS or srfi-1

;;; Copyright (C) 2003, 2006 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 3 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?))