Re: splitting a class in pieces, compile-time dependent

[Richard Frith-Macdonald]

On 27 Jul 2013, at 09:34, Riccardo Mottola <riccardo.mottola@libero.it> wrote:

> Hi,
> 
> MicheleBert . wrote:
>> 2013/7/23 Riccardo Mottola <riccardo.mottola@libero.it>:
>>> I want to find  a good way to split this in MyClass-A, MyClass-B, etc by
>>> adding the least possible logic and especially keeping everything static ad
>>> build time (not runtime).
>> I am not sure I understood well, but I can guess a suggestion?
>> Could be done something like following? (I write in C++, but I think
>> there is an objc equivalent)
>> 
>> class MyClassSpecific
>> {
>> #if defined(_A_)
>>  <A stuff>
>> #elif defined(_B_)
>>   <B stuff>
>> #endif
>> };
>> 
>> class MyClass : public MyClassSpecific
>> {
>>   <common stuff>
>> };
> That is essentially quite similar to the beginning code. But how do you split 
> this in different files?
> 
> I ended up implementing David's version which actually works (thanks David).
> The only thing which I don't like about that version is that the different 
> files are "included" in a class implementation file (.m) and not explicitly 
> in the makefile. I essentially tried to do the same thing, but with explicit 
> separation of headers and of course it didn't work.
> If such a project had to be managed in ProjectCenter it wouldn't work, for 
> example: project files are added automatically to the make file. I checked 
> and "make dist" works, but it still might pose problems when distribution 
> make package lists.
> 
> I still have stuff to improve, but for now I like the first clean-up, it made 
> the code (and also the necessary imports) much much better. The only dirty 
> part is actually my linux code which has tons of ivars.

If you have common ivars, then you could just put all the system-specific code 
in separate categories in separate files:

@interface MyClass : BaseClass
{
// ivars
}
// comon methods
@end

@interface MyClass (SystemDependentMethods)
// ... mthod declarations
@end

So you just put different implemmentation of MyClass (SystemDependentMethods) 
in different files.