[RFC/base] -description for non-property-list object in collections

[David Ayers]

Hello everyone,

While porting an application which encodes it's data into manually 
assembled plists, I stumbled on the following issue.

When custom objects, who's -description is designed to be in property 
list format, are inserted into NSArray's or NSDictionary's and these are 
then sent -description for an aggregated plist, the current 
NSPropertyList implementation quotes the the non-plist object's 
description.  I'm not sure how Cocoa handles this but OPENSTEP did not 
quote those descriptions.

I'm proposing the following patch, which will attempt to parse the 
description into a property list and include the returned object in the 
generated description tree instead.  If parsing as a property list 
fails, it falls back to simply using the description.

I'm posting this here in case someone has an objection or an idea for an 
alternative approach.  Save objections, I'll commit it.

Cheers,
David

Index: Source/NSPropertyList.m
===================================================================
RCS file: /cvsroot/gnustep/gnustep/core/base/Source/NSPropertyList.m,v
retrieving revision 1.24
diff -u -r1.24 NSPropertyList.m
--- Source/NSPropertyList.m     22 Feb 2005 11:22:44 -0000      1.24
+++ Source/NSPropertyList.m     26 Feb 2005 16:20:03 -0000
@@ -2002,9 +2002,25 @@
        }
       else
        {
-         NSDebugLog(@"Non-property-list class (%@) encoded as string",
-           NSStringFromClass([obj class]));
-         PString([obj description], dest);
+         NSString *desc;
+         volatile id plobj = nil;
+
+         desc = [obj description];
+         NS_DURING
+           {
+             plobj = [desc propertyList];
+             NSDebugLog(@"Non-property-list class (%@) "
+                        @"encoded as description's property-list",
+                        NSStringFromClass([obj class]));
+           }
+         NS_HANDLER
+           {
+             plobj = desc;
+             NSDebugLog(@"Non-property-list class (%@) encoded as string",
+                        NSStringFromClass([obj class]));
+           }
+         NS_ENDHANDLER
+         OAppend(plobj, loc, lev, step, x, dest);
        }
     }
 }