Re: style question: when to use 'id' as return value?
Re: style question: when to use 'id' as return value?
- Subject: Re: style question: when to use 'id' as return value?
- From: "Sean McBride" <email@hidden>
- Date: Mon, 17 Dec 2007 17:36:04 -0500
- Organization: Rogue Research
On 12/17/07 2:25 PM, Bill Bumgarner said:
>On Dec 17, 2007, at 2:14 PM, Sean McBride wrote:
>> NSString has the method:
>>
>> + (id)stringWithString:(NSString *)aString
>>
>> Why is the return value not an 'NSString*' instead of an 'id'? Is
>> this
>> just a stylistic preference, or...?
>
>Because both NSString and NSMutableString Do The Right Thing when that
>method is invoked and, thus, declaring that the method returns a
>particular type of string -- mutable or immutable -- would be wrong
>half the time.
I see; makes sense, thanks! But this was just one example, there are
other situations where I don't understand how 'id' was chosen over a
concrete type. For example:
+ (id)sharedGlyphGenerator
vs
+ (ABAddressBook *)sharedAddressBook
Likewise, why does NSWindow's -windowController return 'id' and not
'NSWindowController*'?
I'm trying to understand in general...
Cheers,
--
____________________________________________________________
Sean McBride, B. Eng email@hidden
Rogue Research www.rogue-research.com
Mac Software Developer Montréal, Québec, Canada
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