Re: Why the need for the id type?
Re: Why the need for the id type?
- Subject: Re: Why the need for the id type?
- From: Dave Camp <email@hidden>
- Date: Mon, 18 Jun 2007 15:11:12 -0700
On Jun 18, 2007, at 2:57 PM, Chris Williams wrote:
On 6/18/07 2:28 PM, "Greg Titus" <email@hidden> wrote:
In this code:
id foo;
[foo someRandomMethod];
As long as -someRandomMethod exists _anywhere_ on any class, it will
work. Importantly, -someRandomMethod can be implemented on many
classes which DO NOT share any common root class, and the code will
work.
Important distinction -- it will COMPILE. I may NOT work. In
fact, it
could fail in a very ugly fashion at runtime if in fact foo is not
an object
with -someRandomMethod by that point.
... or does not handle -someRandomMethod with a forward invocation
(e.g. a proxy object or whatever). Also, NSProxy is another example
of something that is a root class; it does not inherit from NSObject
but instead implements the NSObject protocol.
Dave
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