oop/goops/active-slot.scm

   1 ;;; installed-scm-file
   2
   3 ;;;;    Copyright (C) 1999 Free Software Foundation, Inc.
   4 ;;;;
   5 ;;;; This program is free software; you can redistribute it and/or modify
   6 ;;;; it under the terms of the GNU General Public License as published by
   7 ;;;; the Free Software Foundation; either version 2, or (at your option)
   8 ;;;; any later version.
   9 ;;;;
  10 ;;;; This program is distributed in the hope that it will be useful,
  11 ;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 ;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 ;;;; GNU General Public License for more details.
  14 ;;;;
  15 ;;;; You should have received a copy of the GNU General Public License
  16 ;;;; along with this software; see the file COPYING.  If not, write to
  17 ;;;; the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  18 ;;;; Boston, MA 02111-1307 USA
  19 ;;;;
  20 \f
  21
  22 ;;;; This software is a derivative work of other copyrighted softwares; the
  23 ;;;; copyright notices of these softwares are placed in the file COPYRIGHTS
  24 ;;;;
  25 ;;;; This file is based upon active-slot.stklos from the STk
  26 ;;;; distribution by Erick Gallesio <eg@unice.fr>.
  27 ;;;;
  28
  29 (define-module (oop goops active-slot)
  30   :use-module (oop goops internal))
  31
  32 (export <active-class>)
  33
  34 (define-class <active-class> (<class>))
  35
  36 (define-method compute-get-n-set ((class <active-class>) slot)
  37   (if (eq? (slot-definition-allocation slot) #:active)
  38       (let* ((index       (slot-ref class 'nfields))
  39              (name        (car slot))
  40              (s           (cdr slot))
  41              (env         (class-environment class))
  42              (before-ref  (get-keyword #:before-slot-ref  s #f))
  43              (after-ref   (get-keyword #:after-slot-ref   s #f))
  44              (before-set! (get-keyword #:before-slot-set! s #f))
  45              (after-set!  (get-keyword #:after-slot-set!  s #f))
  46              (unbound     (make-unbound)))
  47         (slot-set! class 'nfields (+ index 1))
  48         (list (lambda (o)
  49                 (if before-ref
  50                     (if (before-ref o)
  51                         (let ((res (%fast-slot-ref o index)))
  52                           (and after-ref (not (eqv? res unbound)) (after-ref o))
  53                           res)
  54                         (make-unbound))
  55                     (let ((res (%fast-slot-ref o index)))
  56                       (and after-ref (not (eqv? res unbound)) (after-ref o))
  57                       res)))
  58
  59               (lambda (o v)
  60                 (if before-set!
  61                     (if (before-set! o v)
  62                         (begin
  63                           (%fast-slot-set! o index v)
  64                           (and after-set! (after-set! o v))))
  65                     (begin
  66                       (%fast-slot-set! o index v)
  67                       (and after-set! (after-set! o v)))))))
  68       (next-method)))