From f841e99836664af5cb722c92715c93f44e8c3e2c Mon Sep 17 00:00:00 2001
From: Robby Findler <robby@racket-lang.org>
Date: Fri, 21 Jun 1996 16:12:42 +0000
Subject: [PATCH] fixed debug again and added indents prefs

original commit: 61339e5b474214c5275ca1ae1b44f4ef81d10c51
---
 collects/mred/prefs.ss | 86 +++++++++++++++++++++++++-----------------
 1 file changed, 51 insertions(+), 35 deletions(-)

diff --git a/collects/mred/prefs.ss b/collects/mred/prefs.ss
index 157a4adb..7b3adc00 100644
--- a/collects/mred/prefs.ss
+++ b/collects/mred/prefs.ss
@@ -10,7 +10,7 @@
     (import ([unit mred:debug : mred:debug^]
 	     [unit mred:exn : mred:exn^]
 	     [unit mzlib:function : mzlib:function^]))
-
+    
     (mred:debug:printf 'invoke "mred:preferences@")
     
     (define preferences-filename
@@ -24,13 +24,26 @@
     
     (define-struct un/marshall (marshall unmarshall))
     
+    (define-struct marshalled (data))
+    
     (define get-preference-box
       (lambda (p) 
-	(hash-table-get preferences p
-			(lambda () 
-			  (raise (mred:exn:make-exn:unknown-preference
-				  (format "unknown preference: ~a" p)
-				  ((debug-info-handler))))))))
+	(let ([ans (hash-table-get preferences p
+				   (lambda () 
+				     (raise (mred:exn:make-exn:unknown-preference
+					     (format "unknown preference: ~a" p)
+					     ((debug-info-handler))))))])
+	  (if (marshalled? ans)
+	      (let* ([marshalled (marshalled-data ans)]
+		     [unmarshalled 
+		      ((un/marshall-unmarshall
+			(hash-table-get marshall-unmarshall p
+					(lambda () mzlib:function:identity)))
+		       marshalled)]
+		     [boxed (box unmarshalled)])
+		(hash-table-put! preferences p boxed)
+		boxed)
+	      ans))))
     
     (define get-preference (mzlib:function:compose unbox get-preference-box))
     
@@ -65,41 +78,44 @@
 	(for-each (lambda (x) (apply set-preference x)) 
 		  defaults)))
     
+    
     (define save-user-preferences 
-      (lambda () 
-	(let ([marshall-pref
-	       (lambda (p boxed-value)
-		 (let* ([value (unbox boxed-value)]
-			[marshalled
-			 (let/ec k
-			   ((un/marshall-marshall
-			     (hash-table-get marshall-unmarshall p
-					     (lambda ()
-					       (k value))))
-			    value))])
-		   (list p marshalled)))])
-	(call-with-output-file preferences-filename
-	  (lambda (p)
-	    (write (hash-table-map preferences marshall-pref) p))
-	  'replace))))
+      (let ([marshall-pref
+	     (lambda (p boxed-value)
+	       (let* ([value (unbox boxed-value)]
+		      [marshalled
+		       (let/ec k
+			 ((un/marshall-marshall
+			   (hash-table-get marshall-unmarshall p
+					   (lambda ()
+					     (k value))))
+			  value))])
+		 (list p marshalled)))])
+	(lambda () 
+	  (call-with-output-file preferences-filename
+	    (lambda (p)
+	      (write (hash-table-map preferences marshall-pref) p)
+	      'replace)))))
     
     (define read-user-preferences 
-      (lambda ()
-	(let ([unmarshall-update
-	       (lambda (input)
-		 (let* ([p (mzlib:function:first input)]
-			[marshalled (mzlib:function:second input)]
-			[unmarshalled 
-			 (let/ec k
-			   ((un/marshall-unmarshall
-			     (hash-table-get marshall-unmarshall p
-					     (lambda () (k marshalled))))
-			    marshalled))])
-		   (set-preference p unmarshalled)))])
+      (let ([unmarshall-pref
+	     (lambda (input)
+	       (let ([p (mzlib:function:first input)]
+		     [marshalled (mzlib:function:second input)])
+		 (let/ec k
+		   (let* ([not-in-table
+			   (lambda ()
+			     (k (hash-table-put! preferences p (make-marshalled marshalled))))]
+			  [ht-pref (hash-table-get preferences p not-in-table)]
+			  [unmarshall (hash-table-get marshall-unmarshall p (lambda () mzlib:function:identity))])
+		     (if (box? ht-pref)
+			 (set-box! ht-pref (unmarshall marshalled))
+			 (set-marshalled-data! marshalled))))))])
+	(lambda ()
 	  (when (file-exists? preferences-filename)
 	    (let ([input (call-with-input-file preferences-filename read)])
 	      (when (list? input)
-		(for-each unmarshall-update input)))))))
+		(for-each unmarshall-pref input)))))))
     
     (define preferences-dialog
       (lambda ()