57 lines
2.1 KiB
Plaintext
57 lines
2.1 KiB
Plaintext
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;;;;
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;;;; a c t i v e - s l o t . s t k l o s -- Active slots metaclass
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;;;;
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;;;; Copyright <20> 1996-1998 Erick Gallesio - I3S-CNRS/ESSI <eg@unice.fr>
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;;;;
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;;;; Permission to use, copy, and/or distribute this software and its
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;;;; documentation for any purpose and without fee is hereby granted, provided
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;;;; that both the above copyright notice and this permission notice appear in
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;;;; all copies and derived works. Fees for distribution or use of this
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;;;; software or derived works may only be charged with express written
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;;;; permission of the copyright holder.
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;;;; This software is provided ``as is'' without express or implied warranty.
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;;;;
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;;;; $Id: active-slot.stklos 1.1 Tue, 03 Feb 1998 11:13:08 +0100 eg $
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;;;;
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;;;; Author: Erick Gallesio [eg@unice.fr]
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;;;; Creation date: 17-Oct-1996 18:16
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;;;; Last file update: 3-Feb-1998 10:13
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(select-module STklos)
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(define-class <Active-metaclass> (<class>)
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())
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(define-method compute-get-n-set ((class <Active-metaclass>) slot)
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(if (eq? (get-slot-allocation slot) :active)
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(let* ((index (slot-ref class 'nfields))
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(name (car slot))
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(s (cdr slot))
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(env (class-environment class))
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(before-ref (make-closure (get-keyword :before-slot-ref s #f) env))
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(after-ref (make-closure (get-keyword :after-slot-ref s #f) env))
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(before-set! (make-closure (get-keyword :before-slot-set! s #f) env))
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(after-set! (make-closure (get-keyword :after-slot-set! s #f) env))
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(unbound (make-unbound)))
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(slot-set! class 'nfields (+ index 1))
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(list (lambda (o)
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(if before-ref
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(if (before-ref o)
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(let ((res (%fast-slot-ref o index)))
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(and after-ref (not (eqv? res unbound)) (after-ref o))
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res)
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(make-unbound))
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(let ((res (%fast-slot-ref o index)))
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(and after-ref (not (eqv? res unbound)) (after-ref o))
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res)))
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(lambda (o v)
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(if before-set!
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(when (before-set! o v)
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(%fast-slot-set! o index v)
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(and after-set! (after-set! o v)))
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(begin
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(%fast-slot-set! o index v)
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(and after-set! (after-set! o v)))))))
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(next-method)))
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