add dynamic-wind test cases

t/dynamic-wind.scm

@@ -0,0 +1,61 @@
+(define (print obj)
+  (write obj)
+  (newline)
+  obj)
+
+(print
+ (dynamic-wind
+     (lambda () (print 'before1))
+     (lambda ()
+       (define cont #f)
+       (print 1)
+       (dynamic-wind
+	   (lambda () (print 'before2))
+	   (lambda ()
+	     (print 2)
+	     (set! cont (call/cc values)))
+	   (lambda () (print 'after2)))
+       (dynamic-wind
+	   (lambda () (print 'before3))
+	   (lambda ()
+	     (print 3)
+	     (if (procedure? cont)
+		 (cont 42)
+		 cont))
+	   (lambda () (print 'after3))))
+     (lambda () (print 'after1))))
+
+; before1
+; 1
+; before2
+; 2
+; after2
+; before3
+; 3
+; after3
+; before2
+; after2
+; before3
+; 3
+; after3
+; after1
+; => 42
+
+(print
+ (let ((path '())
+       (c #f))
+   (let ((add (lambda (s)
+		(set! path (cons s path)))))
+     (dynamic-wind
+	 (lambda () (add 'connect))
+	 (lambda ()
+	   (add (call-with-current-continuation
+		 (lambda (c0)
+		   (set! c c0)
+		   'talk1))))
+	 (lambda () (add 'disconnect)))
+     (if (< (length path) 4)
+	 (c 'talk2)
+	 (reverse path)))))
+
+; (connect talk1 disconnect connect talk2 disconnect)