Re[2]: NSString changes breaks...

[Manuel Guesdon]

On Tue, 31 Oct 2000 17:35:08 +0000 Richard wrote:
 >| The -initWithCharactersNoCopy:length:freeWhenDone: is currently a primitive 
 >for NSString and 
 >| -initWithCapacity: is primitive for NSMutableString, but I'm not sure if 
 >NSMutableString should
 >| implement -initWithCharactersNoCopy:length:freeWhenDone: using 
 >-initWithCapacity: and -replaceCharactersInRange:withString:.  At present, it 
 >doesn't.
 >| 
 >| > GSWElementIDString doesn't have any ivar. It's just an empty class with a 
 >category. 
 >| 
 >| If it has no ivars, how dis it expected to work?

I think I haven't understand completely how NSStrings work. I was thinking my 
GSWElementIDString class use NSMutableString ivars and methods. I've checked 
the previous core/base code and found no ivar in NSMutableString too.

What I understand now, please correct me if I'm wrong:
        If I do a id s1=[NSMutableString new], I get a GSMString*
        If I do a id s2=[GSWElementIDString new], I get a GSWElementIDString* 
(if GSWElementIDString has no specific init method).

        If I do a [s1 appendString:@"toto"], it call NSMutableString 
appendString: method but only because GSMString inherit from NSMutableString.
        Same thing for s2.

What I don't understand:
        GSWElementIDString was working well with no ivar and without 
implementing -initXXX3. Why ? In this logic, it wasn't possible because it 
shouldn't have ivars nor -initXXX methods.

You can see the code in gsweb/GSWeb.framework/GSWElementIDString.[hm]


 >| To subclass NSMutableString, you should be inheriting from NSMutableString 
 >and implementing
 >| (at least) -replaceCharactersInRange:withString:, -length, 
 >-characterAtindex:
 >| 
 >| As the code stands now, you also have to implement the designated 
 >initialisers -
 >| -initWithCharactersNoCopy:length:freeWhenDone:
 >| -initWithCStringNoCopy:length:freeWhenDone:
 >| -initWithCapacity:

I can do this but why should I reimplement GSMString (for example) as I only 
want a working MutableString which differ only by the class name and few added 
methods ? I can do this by subsclassing GSMString but it's not the right way 
for portability.

Sorry to ask newbie questions :-)

Manuel
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