scsh-0.5/alt/weak.scm

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1995-10-13 23:34:21 -04:00
; Copyright (c) 1993, 1994 Richard Kelsey and Jonathan Rees. See file COPYING.
(define (make-weak-pointer x) (cons '<weak> x))
(define weak-pointer-ref cdr)
(define (weak-pointer? x)
(and (pair? x) (eq? (car x) '<weak>)))