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;;;; "dwindtst.scm", routines for characterizing dynamic-wind.
;Copyright (C) 1992 Aubrey Jaffer
;
;Permission to copy this software, to modify it, to redistribute it,
;to distribute modified versions, and to use it for any purpose is
;granted, subject to the following restrictions and understandings.
;
;1. Any copy made of this software must include this copyright notice
;in full.
;
;2. I have made no warrantee or representation that the operation of
;this software will be error-free, and I am under no obligation to
;provide any services, by way of maintenance, update, or otherwise.
;
;3. In conjunction with products arising from the use of this
;material, there shall be no use of my name in any advertising,
;promotional, or sales literature without prior written consent in
;each case.
(require 'dynamic-wind)
(define (dwtest n)
(define cont #f)
(display "testing escape from thunk") (display n) (newline)
(display "visiting:") (newline)
(call-with-current-continuation
(lambda (x) (set! cont x)))
(if n
(dynamic-wind
(lambda ()
(display "thunk1") (newline)
(if (eqv? n 1) (let ((ntmp n))
(set! n #f)
(cont ntmp))))
(lambda ()
(display "thunk2") (newline)
(if (eqv? n 2) (let ((ntmp n))
(set! n #f)
(cont ntmp))))
(lambda ()
(display "thunk3") (newline)
(if (eqv? n 3) (let ((ntmp n))
(set! n #f)
(cont ntmp)))))))
(define (dwctest n)
(define cont #f)
(define ccont #f)
(display "creating continuation thunk") (newline)
(display "visiting:") (newline)
(call-with-current-continuation
(lambda (x) (set! cont x)))
(if n (set! n (- n)))
(if n
(dynamic-wind
(lambda ()
(display "thunk1") (newline)
(if (eqv? n 1) (let ((ntmp n))
(set! n #f)
(cont ntmp))))
(lambda ()
(call-with-current-continuation
(lambda (x) (set! ccont x)))
(display "thunk2") (newline)
(if (eqv? n 2) (let ((ntmp n))
(set! n #f)
(cont ntmp))))
(lambda ()
(display "thunk3") (newline)
(if (eqv? n 3) (let ((ntmp n))
(set! n #f)
(cont ntmp))))))
(cond
(n
(set! n (- n))
(display "testing escape from continuation thunk") (display n) (newline)
(display "visiting:") (newline)
(ccont #f))))
(dwtest 1) (dwtest 2) (dwtest 3)
(dwctest 1) (dwctest 2) (dwctest 3)
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