Re: isa
Re: isa
- Subject: Re: isa
- From: Phillip Morelock <email@hidden>
- Date: Sun, 02 Jun 2002 21:16:11 -0700
On 6/2/02 7:23 PM, "Aram Greenman" <email@hidden> wrote:
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On Sunday, June 2, 2002, at 01:23 AM, Marcel Weiher wrote:
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> On Saturday, June 1, 2002, at 11:22 Uhr, Aram Greenman wrote:
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>> The thread where this originally came up (re. ObjC inits vs. C++
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>> constructors) had to do with sending messages to self in an
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>> initalizer, which is _usually_ a bad idea,
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>
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> No. In Objective-C it is not "usually" considered a bad idea at all.
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>> since it is possible the method called might access unitialized
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>> instance variables, depending on where you are in the initializer
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>> chain.
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> Well, don't call methods that might access uninitialized instance
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> variables, then!
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Yes, of course, but what if (probably the third time this has been
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brought up between this thread and the previous one) class A sends [self
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foo] in -init or whatever its designated initializer is. -[A foo]
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doesn't access any uninitialized instance variables. A is later
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subclassed by A', which overrides -foo with an implementation which
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accesses instance variables declared in A' (and therefore will _always_
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be uninitialized when -[A init] is called by -[A' init]). Now the
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seemingly safe message [self foo] in -[A init] could potentially cause
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unexpected behavior.
self = [super init];
fillup "the newbie" morelock
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I admit that this is _not_ that big of a deal, and is avoidable by
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common sense and documentation, however, IMHO it is better to provide
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for the possibility that someone (possibly yourself) might subclass your
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class without looking at the code in question or reading your comments.
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>
Aram
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| References: | |
| | >Re: isa (From: Aram Greenman <email@hidden>) |