Re: What, exactly constitutes a mutable action on an instance?
Re: What, exactly constitutes a mutable action on an instance?
- Subject: Re: What, exactly constitutes a mutable action on an instance?
- From: Alex Zavatone <email@hidden>
- Date: Tue, 28 May 2013 10:44:30 -0400
On May 28, 2013, at 9:46 AM, Steve Mills wrote:
> On May 28, 2013, at 08:39:21, Alex Zavatone <email@hidden> wrote:
>
>> Though it's clearly defined in the docs when to use NSMubleAnything vs. NSAnything (insert Array, Dictionary, String, etc for Anything), there is no compiler warning when you perform a simple action such as allocate a string and then reassign values to it.
>>
>> With this in mind, what exactly constitutes a mutable action?
>>
>> If we take this:
>>
>> NSString *myString;
>> myString = @"Hi";
>> myString = @"Hi there";
>>
>> I'm clearly expecting some type of warning from the compiler when myString is redefined, but I don't see one in Xcode 4.6.1. Is this redefinition not a mutable action? It sure seems like it is.
>
> The example you've given is not changing the string, it's simply pointing the string pointer to a new string (changing the address it points to). This would require a mutable string:
>
> [myString appendString:@"Hi there"];
>
> because it's changing the string, but it will leave myString at the same pointer address.
Excellent. This is part of the information that I'm looking for.
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