Re: Making an object accessible by both MyDocument AND a custom class
Re: Making an object accessible by both MyDocument AND a custom class
- Subject: Re: Making an object accessible by both MyDocument AND a custom class
- From: David Remahl <email@hidden>
- Date: Wed, 25 Sep 2002 20:44:29 +0200
>
> You certainly CAN send messages to nil! I do it all the time.
>
>
Sure you can.
>
>
> It sends the message up the responder chain.
>
>
No it does not. At least I dearly hope it does not!
>
>
From Apple's "Object-Oriented Programming and the Objective-C
>
Language", June 2000, chapter 3, page 53:
>
>
"A message to nil is also valid, as long as the message returns an
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object; if it does, a message sent to nil will return nil. If the
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message sent to nil returns anything other than an object, the return
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value is undefined."
An _action_ with a target of nil will target the first responder and walk
down the responder chain.
A simple message to nil will not have the same effect. To send an action in
that way:
[NSApp sendAction:[self action] to:[self target] from:self];
>
> Have you not heard of a nil target before? Can I get a witness out
>
> there please?
>
>
I'm sorry. :}
Nil target != nil receiver, in this case.
/ Rgds, David
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