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guile/oop/goops/composite-slot.scm
2005-05-23 20:15:36 +00:00

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;;; installed-scm-file
;;;; Copyright (C) 1999, 2000, 2001 Free Software Foundation, Inc.
;;;;
;;;; This program is free software; you can redistribute it and/or modify
;;;; it under the terms of the GNU General Public License as published by
;;;; the Free Software Foundation; either version 2, or (at your option)
;;;; any later version.
;;;;
;;;; This program 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 General Public License for more details.
;;;;
;;;; You should have received a copy of the GNU General Public License
;;;; along with this software; see the file COPYING. If not, write to
;;;; the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
;;;; Boston, MA 02110-1301 USA
;;;;
;;;; As a special exception, the Free Software Foundation gives permission
;;;; for additional uses of the text contained in its release of GUILE.
;;;;
;;;; The exception is that, if you link the GUILE library with other files
;;;; to produce an executable, this does not by itself cause the
;;;; resulting executable to be covered by the GNU General Public License.
;;;; Your use of that executable is in no way restricted on account of
;;;; linking the GUILE library code into it.
;;;;
;;;; This exception does not however invalidate any other reasons why
;;;; the executable file might be covered by the GNU General Public License.
;;;;
;;;; This exception applies only to the code released by the
;;;; Free Software Foundation under the name GUILE. If you copy
;;;; code from other Free Software Foundation releases into a copy of
;;;; GUILE, as the General Public License permits, the exception does
;;;; not apply to the code that you add in this way. To avoid misleading
;;;; anyone as to the status of such modified files, you must delete
;;;; this exception notice from them.
;;;;
;;;; If you write modifications of your own for GUILE, it is your choice
;;;; whether to permit this exception to apply to your modifications.
;;;; If you do not wish that, delete this exception notice.
;;;;
;;;; This software is a derivative work of other copyrighted softwares; the
;;;; copyright notices of these softwares are placed in the file COPYRIGHTS
;;;;
;;;; This file is based upon composite-slot.stklos from the STk
;;;; distribution by Erick Gallesio <eg@unice.fr>.
;;;;
(define-module (oop goops composite-slot)
:use-module (oop goops)
:export (<composite-class>))
;;;
;;; (define-class CLASS SUPERS
;;; ...
;;; (OBJECT ...)
;;; ...
;;; (SLOT #:allocation #:propagated
;;; #:propagate-to '(PROPAGATION ...))
;;; ...
;;; #:metaclass <composite-class>)
;;;
;;; PROPAGATION ::= OBJECT | (OBJECT TARGETSLOT)
;;;
;;; The slot SLOT will be propagated to the slot TARGETSLOT in the object
;;; stored in slot OBJECT. If TARGETSLOT is omitted, assume that the target
;;; slot is named SLOT.
;;;
(define-class <composite-class> (<class>))
(define-method (compute-get-n-set (class <composite-class>) slot)
(if (eq? (slot-definition-allocation slot) #:propagated)
(compute-propagated-get-n-set slot)
(next-method)))
(define (compute-propagated-get-n-set s)
(let ((prop (get-keyword #:propagate-to (cdr s) #f))
(s-name (slot-definition-name s)))
(if (not prop)
(goops-error "Propagation not specified for slot ~S" s-name))
(if (not (pair? prop))
(goops-error "Bad propagation list for slot ~S" s-name))
(let ((objects (map (lambda (p) (if (pair? p) (car p) p)) prop))
(slots (map (lambda (p) (if (pair? p) (cadr p) s-name)) prop)))
(let ((first-object (car objects))
(first-slot (car slots)))
(list
;; The getter
(lambda (o)
(slot-ref (slot-ref o first-object) first-slot))
;; The setter
(if (null? (cdr objects))
(lambda (o v)
(slot-set! (slot-ref o first-object) first-slot v))
(lambda (o v)
(for-each (lambda (object slot)
(slot-set! (slot-ref o object) slot v))
objects
slots))))))))