From 18f91ae67d53cc0b77c68a958f55b571e030c1dc Mon Sep 17 00:00:00 2001
From: Chris Hanson <org/chris-hanson/cph>
Date: Thu, 1 Nov 2018 20:31:37 -0700
Subject: [PATCH] Don't print internals of promises.

---
 src/runtime/pp.scm | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/runtime/pp.scm b/src/runtime/pp.scm
index 8dda0635d..a14c04793 100644
--- a/src/runtime/pp.scm
+++ b/src/runtime/pp.scm
@@ -196,7 +196,9 @@ USA.
        `((weak-car ,(weak-car wp))
 	 (weak-cdr ,(weak-cdr wp)))))
 
-   (define-pp-describer cell?
+   (define-pp-describer (lambda (object)
+			  (and (cell? object)
+			       (not (promise? object))))
      (lambda (cell)
        `((contents ,(cell-contents cell)))))))
 
-- 
2.25.1