From e29ada38db575e4edca2f899487a69c8c32bbe85 Mon Sep 17 00:00:00 2001
From: Chris Hanson <org/chris-hanson/cph>
Date: Mon, 1 Jun 1992 22:24:40 +0000
Subject: [PATCH] Add option to disable special handling of undefined values.

---
 v7/src/6001/make.scm      | 7 +++++--
 v7/src/runtime/usrint.scm | 9 ++++++---
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/v7/src/6001/make.scm b/v7/src/6001/make.scm
index cf4be1806..83eae9d6d 100644
--- a/v7/src/6001/make.scm
+++ b/v7/src/6001/make.scm
@@ -1,6 +1,6 @@
 #| -*-Scheme-*-
 
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/6001/make.scm,v 15.4 1992/04/13 20:10:23 cph Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/6001/make.scm,v 15.5 1992/06/01 22:24:40 cph Exp $
 
 Copyright (c) 1991-92 Massachusetts Institute of Technology
 
@@ -38,7 +38,7 @@ MIT in each case. |#
 
 (package/system-loader "6001" '() 'QUERY)
 ((access initialize-package! (->environment '(student scode-rewriting))))
-(add-system! (make-system "6.001" 15 3 '()))
+(add-system! (make-system "6.001" 15 5 '()))
 
 (set! repl:allow-restart-notifications? false)
 (set! repl:write-result-hash-numbers? false)
@@ -46,6 +46,9 @@ MIT in each case. |#
 (set! *unparse-compound-procedure-names?* false)
 (set! *pp-default-as-code?* true)
 (set! x-graphics:auto-raise? true)
+(set! (access write-result:undefined-value-is-special?
+	      (->environment '(RUNTIME USER-INTERFACE)))
+      false)
 
 (in-package (->environment '(edwin))
   (set! editor-can-exit? false)
diff --git a/v7/src/runtime/usrint.scm b/v7/src/runtime/usrint.scm
index ab00c9aa9..2ea069bb8 100644
--- a/v7/src/runtime/usrint.scm
+++ b/v7/src/runtime/usrint.scm
@@ -1,8 +1,8 @@
 #| -*-Scheme-*-
 
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/runtime/usrint.scm,v 1.1 1991/11/26 07:45:00 cph Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/runtime/usrint.scm,v 1.2 1992/06/01 22:23:16 cph Exp $
 
-Copyright (c) 1991 Massachusetts Institute of Technology
+Copyright (c) 1991-92 Massachusetts Institute of Technology
 
 This material was developed by the Scheme project at the Massachusetts
 Institute of Technology, Department of Electrical Engineering and
@@ -185,7 +185,8 @@ MIT in each case. |#
     (lambda ()
       (fresh-line port)
       (write-string ";" port)
-      (if (undefined-value? object)
+      (if (and write-result:undefined-value-is-special?
+	       (undefined-value? object))
 	  (write-string "No value" port)
 	  (begin
 	    (write-string "Value" port)
@@ -196,6 +197,8 @@ MIT in each case. |#
 	    (write-string ": " port)
 	    (write object port))))))
 
+(define write-result:undefined-value-is-special? true)
+
 (define (port/set-default-directory port directory)
   (let ((operation (port/operation port 'SET-DEFAULT-DIRECTORY)))
     (if operation
-- 
2.25.1