Re: NSString methods returns GSUnicodeString, why?

[Richard Frith-Macdonald]

On Monday, July 2, 2001, at 04:32 PM, Laurent Julliard wrote:

> All,
>
> I'm in the process of writing a Ruby to GNUstep binding. And I have
> difficutlies to understand the following problem. A simple piece of Ruby
> code illustrates the problem (irb is the Ruby interactive shell):
>
> irb> a = NSString.new    # create a new NSString object
> irb> a.initWithCString("GNUstep forever")
> irb> a.length
> 15
>
> Everything seems to be working fine. But...
>
> irb> a.cString
> Uncaught exception NSCharacterConversionException, reason: Can't get
> cString from Unicode string.
>
> Right after the initWithCString method call I have put some logs showing
> that initWithCString actually returns a GSUnicodeString object instead
> of a NSString object as you would expect. It looks like GSUnicodeString
> is a subclass of GSString which in turn is a subclass of NSString. So
> why isn't the cString method call working?
>
> Any idea is welcome.

Assuming that the line -

irb> a = NSString.new    # create a new NSString object

is calling the 'new' method (a cover for an alloc followed by an init),
what is actually happening is that you are doing -

[NSString alloc]  (returns a placeholder string)
init    (transmutes placeholder to a concrete unicode string)
initWithCString:  (illegal ... already initialised)


So theres's a problem in GNUstep ... it should really have raised an 
exception
when you tried to do the initWithCString:, and a problem in your 
code ... it
should have done alloc rather than new.