[MacRuby-devel] Need to Write Core Data Accessors in MacRuby?

[Robert Lowe]

Value must be a pointer when passed

value_to_pointer = Pointer.new(:object)
value_to_pointer.assign(value)

Regards,
  - Rob

On 2011-06-28, at 12:08 PM, Eloy Duran <eloy at dekleineprins.me> wrote:

> I have no experience with Core Data, but if you are looking to make
> repetitive work easy then don't forget about the metaprogramming
> possibilities with Ruby. Taking your example, you could create class
> method like the following:
>
> class Model
>  def self.core_data_accessor(name)
>    class_eval(%{
>      def add#{name}Object(value)
>        changedObjects = NSSet.setWithObject(value)
>        willChangeValueForKey('#{name}',
> withSetMutation:NSKeyValueUnionSetMutation,
> usingObjects:changedObjects)
>        primitiveValueForKey('#{name}').addObject(value)
>        didChangeValueForKey('#{name}',
> withSetMutation:NSKeyValueUnionSetMutation,
> usingObjects:changedObjects)
>      end
>    })
>  end
>
>  core_data_accessor 'SubFolders'
>  core_data_accessor 'OtherFolders'
>  # etc
> end
>
> HTH
>
> On Tue, Jun 28, 2011 at 5:55 PM, Shannon Love <techzen at me.com> wrote:
>> I'm not to the point of wiring up the UI yet. I will employ  
>> bindings when I
>> do so but at the moment I am creating a complex data model using
>> NSManagedObject subclasses with lots of customized behaviors. I do  
>> this all
>> the time in Objective-c but I am uncertain how to go about doing so  
>> in
>> MacRuby.
>>  The @dynamic processor in Objective-C 2.0 autogenerates attribute  
>> and
>> relationship accessors except for the to-many relationship  
>> convenience
>> methods but obviously MacRuby has no such capability. I don't think  
>> the
>> `attr_accessor ` in ruby will generate the proper core data  
>> accessors.
>> I suppose my real question is: Do we have to write all the  
>> accessors like we
>> used to do in the early days of Core Data in Objective-s 1.0 or is  
>> there
>> some functionality in ruby or MacRuby that obviates the need to do  
>> so?
>> Thanks,
>> Shannon
>>
>>
>> On Jun 27, 2011, at 5:55 PM, Matt Aimonetti wrote:
>>
>> Hey Shannon,
>> I'm not sure I fully understand, but you should be able to just set  
>> the
>> accessor and do the binding via Xcode as shown
>> here: http://ofps.oreilly.com/titles/9781449380373/_core_data.html
>> Let me know if that doesn't answer your question.
>> - Matt
>>
>> On Mon, Jun 27, 2011 at 3:45 PM, Shannon Love <techzen at me.com> wrote:
>>>
>>> Howdy,
>>>
>>> I've Core Data a lot in Objective-c and now I am trying to use it in
>>> MacRuby. It occurs to me that I might need to create the to-many
>>> relationship accessors just like you have to do in Objective-C.
>>>
>>> To clarify: Suppose I have a data model that models a file  
>>> structure and
>>> which looks like this:
>>>
>>> Folder{
>>>   name:string
>>>   parent<<-->Folder.subFolders
>>>   subFolders<-->>Folder.parent
>>>   files<-->>File.folder
>>> }
>>> File{
>>>   name:string
>>>   folder<<-->Folder.file
>>> }
>>>
>>> In Objective-C, I would normally have methods in the `Folder`  
>>> class that
>>> would look like:
>>>
>>> addSubFoldersObject:
>>> removeSubFoldersObject:
>>> addSubFoldersObjects:
>>> removeSubFoldersObjects:
>>>
>>> The methods themselves would use look something like:
>>>
>>> - (void)addSubFoldersObject:(FetchedPropertyExtractor *)value {
>>>     NSSet *changedObjects = [[NSSet alloc] initWithObjects:&value
>>> count:1];
>>>     [self willChangeValueForKey:@"SubFolders"
>>> withSetMutation:NSKeyValueUnionSetMutation  
>>> usingObjects:changedObjects];
>>>     [[self primitiveValueForKey:@"SubFolders"] addObject:value];
>>>     [self didChangeValueForKey:@"SubFolders"
>>> withSetMutation:NSKeyValueUnionSetMutation  
>>> usingObjects:changedObjects];
>>>     [changedObjects release];
>>> }
>>>
>>> Do you have to do the same thing in MacRuby or will the normal  
>>> ruby set
>>> operations suffice?
>>> Thanks,
>>> Shannon Love a.k.a TechZen
>>>
>>>
>>>
>>> _______________________________________________
>>> MacRuby-devel mailing list
>>> MacRuby-devel at lists.macosforge.org
>>> http://lists.macosforge.org/mailman/listinfo.cgi/macruby-devel
>>>
>>
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