Re: attributed string Macro in TalkSoup

[Wolfgang Lux]

Riccardo Mottola wrote:

> do you see anything wrong with this macro?
> 
> #define S2AS(_x) ( (_x) ? [[[NSAttributedString alloc] initWithString: (_x)] 
> autorelease] : nil )
> 
> It is then called by passing a string like @"hi".
> 
> I added the ternary operator to return nil if nil is passed.
> 
> When used in TalkSoup, I get these two errors:
> 
> commands.m:368: warning: the address of '_OBJC_INSTANCE_30' will always 
> evaluate as 'true'
> commands.m: In function '-[TalkSoup(Commands) commandClientinfo:connection:]':

If you look carefully you'll notice that this is a warning and not an error. 
And the compiler is of course right. The condition (_x) expands to (@"hi") and 
that condition always evaluates to true. So the compiler warns you that in this 
particular case the else branch of the conditional can never be reached and 
thus is redundant (and might never be reached by coverage tests).

> main.m: In function '-[NetclassesConnection 
> changeNick:onConnection:withNickname:sender:]':
> main.m:418: warning: pointer type mismatch in conditional expression

And this is also a warning and not an error. It's due to a dumb compiler that 
expects you to use then and else branches in a conditional expression that have 
the same type. This is of course the compiler's fault. The compiler should not 
complain if the expression in one branch is a subtype of the expression in the 
other branch. I think this was fixed in either gcc version 4.6 or 4.7.

Wolfgang