guile/module/oop/goops/util.scm

;;;; 	Copyright (C) 1999, 2000, 2001, 2003, 2006, 2008, 2012 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 (oop goops util)
  :export (mapappend find-duplicate
	   map* for-each* length* improper->proper)
  :use-module (srfi srfi-1)
  :re-export  (any every)
  :no-backtrace
  )


;;;
;;; {Utilities}
;;;

(define mapappend append-map)

(define (find-duplicate l)	; find a duplicate in a list; #f otherwise
  (cond 
    ((null? l)			#f)
    ((memv (car l) (cdr l))	(car l))
    (else 			(find-duplicate (cdr l)))))

(define (map* fn . l) 		; A map which accepts dotted lists (arg lists  
  (cond 			; must be "isomorph"
   ((null? (car l)) '())
   ((pair? (car l)) (cons (apply fn      (map car l))
			  (apply map* fn (map cdr l))))
   (else            (apply fn l))))

(define (for-each* fn . l) 	; A for-each which accepts dotted lists (arg lists  
  (cond 			; must be "isomorph"
   ((null? (car l)) '())
   ((pair? (car l)) (apply fn (map car l)) (apply for-each* fn (map cdr l)))
   (else            (apply fn l))))

(define (length* ls)
  (do ((n 0 (+ 1 n))
       (ls ls (cdr ls)))
      ((not (pair? ls)) n)))

(define (improper->proper ls)
  (if (pair? ls)
      (cons (car ls) (improper->proper (cdr ls)))
      (list ls)))