diff --git a/lang/reader.rkt b/lang/reader.rkt
index 0063fd1..956e1fc 100755
--- a/lang/reader.rkt
+++ b/lang/reader.rkt
@@ -4,6 +4,7 @@
 #:language-info `#((planet cs019/cs019/language-info) 
                    get-info
                    (abbreviate-cons-as-list
+                    show-sharing
                     read-accept-quasiquote
                     use-function-output-syntax))