(make-exchanger): Added. Thanks to Clinton Ebadi!

diff --git a/ice-9/slib.scm b/ice-9/slib.scm
index e91edae..dc40c2e 100644 (file)
--- a/ice-9/slib.scm
+++ b/ice-9/slib.scm
@@ -326,3 +326,6 @@ no other easy or unambiguous way of detecting such features."
          (set-cdr! entry path-name)
          (set! *catalog*
                (acons name path-name *catalog*))))))
+
+(define (make-exchanger obj)
+  (lambda (rep) (let ((old obj)) (set! obj rep) old)))