From a662c679dc50140ac49241bcb534cd5f9a295acd Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Tue, 24 Aug 2010 21:10:08 -0600
Subject: [PATCH] reflect bsl, etc. printer options for external use

---
 collects/htdp/asl/lang/reader.rkt | 3 ++-
 collects/htdp/bsl/reader.rkt      | 1 +
 collects/htdp/bsl/runtime.rkt     | 1 +
 3 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/collects/htdp/asl/lang/reader.rkt b/collects/htdp/asl/lang/reader.rkt
index 7f9e163c58..6ec68bded0 100644
--- a/collects/htdp/asl/lang/reader.rkt
+++ b/collects/htdp/asl/lang/reader.rkt
@@ -1,4 +1,5 @@
 #lang s-exp htdp/bsl/reader
 lang/htdp-intermediate-lambda
 '(abbreviate-cons-as-list
-  read-accept-quasiquote)
+  read-accept-quasiquote
+  show-sharing)
diff --git a/collects/htdp/bsl/reader.rkt b/collects/htdp/bsl/reader.rkt
index 5dd9934c8c..10ffd8517b 100644
--- a/collects/htdp/bsl/reader.rkt
+++ b/collects/htdp/bsl/reader.rkt
@@ -14,6 +14,7 @@
    #:info (make-info options)
    #:language-info (make-language-info options)
 
+   (provide options)
    (define options opts)))
 
 (define (wrap-reader read-proc options)
diff --git a/collects/htdp/bsl/runtime.rkt b/collects/htdp/bsl/runtime.rkt
index 2cbb663275..342754248b 100644
--- a/collects/htdp/bsl/runtime.rkt
+++ b/collects/htdp/bsl/runtime.rkt
@@ -28,6 +28,7 @@
   ;; Set pretty-print options:
   (pretty-print-show-inexactness #t)
   (pretty-print-exact-as-decimal #t)
+  (show-sharing (memq 'show-sharing options))
 
   ;; Set print handlers to use print-convert and pretty-write:
   (current-print