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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)