Re: crash in outlineView:isGroupItem:

FROM : Joan Lluch (casa)
DATE : Sun Jun 08 23:04:05 2008

El 08/06/2008, a las 22:11, Kyle Sluder escribió:

> On Sun, Jun 8, 2008 at 1:37 PM, Joan Lluch (casa) <<email_removed>> 
> wrote:

>>  return ( item && [[item representedObject] isKindOfClass:[GroupNode
>> class]] ) ;

>
> Style note: you don't need to do this.  [[item representedObject]
> isKindOfClass:[GroupNode class]] will work just fine, because messages
> to nil return zero or their logical equivalent.  So if item == nil,
> then [item representedObject] == nil, which means that [[item
> representedObject] isKindOfClass:[GroupNode class]] == NO.
>
> Of course, this all works only if the GroupNode class exists.  ;-)
>
> --Kyle Sluder


Yes, of course, objective-C allows you to send messages to nil but 
coming from a c++ background I just am used to do check for nullity 
first. On the other hand, checking an object for nil in an early stage 
will in some cases give a performance improvement. Not in the above 
code, obviously. :)_______________________________________________

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