56 lines
2.0 KiB
Plaintext
56 lines
2.0 KiB
Plaintext
;;;;
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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 © 1996-1999 Erick Gallesio - I3S-CNRS/ESSI <eg@unice.fr>
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;;;;
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;;;; Permission to use, copy, modify, distribute,and license this
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;;;; software and its documentation for any purpose is hereby granted,
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;;;; provided that existing copyright notices are retained in all
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;;;; copies and that this notice is included verbatim in any
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;;;; distributions. No written agreement, license, or royalty fee is
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;;;; required for any of the authorized uses.
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;;;; This software is provided ``AS IS'' without express or implied
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;;;; warranty.
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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-Sep-1999 20:05 (eg)
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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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