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+;;;; "dwindtst.scm", routines for characterizing dynamic-wind.
+;Copyright (C) 1992 Aubrey Jaffer
+;
+;Permission to copy this software, to redistribute it, 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)