[Kde-bindings] Qt::Object.connect for ruby-blocks

[kelko]

Richard Dale wrote:
> On Monday 04 September 2006 12:05, kelko wrote:
>> Richard Dale wrote:
> 
>>> I'd like to change the other forms of connect() too so they can
>>> take blocks too. Eg:
>>>
>>> connect(a, SIGNAL(:siga), b, SLOT(:slotb)) could have one less
>>> argument and take a block instead:
>>>
>>> connect(a, SIGNAL(:siga), b) { ... }
>> Why would you want to bind a block to a target? (the third argument)
>> For if the block executes in the context of where it was created then I
>> for myself don't see a need for such a thing.
> 
> Here we would expect the blocked to be called in the context of 'self':
> 
> connect(a, SIGNAL(:siga)) { ... }
> 
> But here, I would expect the block to be called in the context of 'b':
> 
> connect(a, SIGNAL(:siga), b) { ... }

Ah, ok,  i see now.

>>> I thought about how the BlockInvocator would work with garbage
>>> collection, and I think we need to give it the target QObject in
>>> its constructor and that would become the parent QObject. Otherwise
>>>  there would be no references to the BlockInvocator in Ruby and it
>>> could get gc'd.
>> Good point about the garbage collector.
>> What about registering the BlockInvocator as child of the source of
>> the signal?
> Because the block is being invoked in the context of the target, not the 
> instance emitting the signal. Therefore it makes more sense to have the 
> target (ie 'b' above) as the QObject parent of the block.

Yes, that would work for the connect(src, sig, target) {} but not for
connect(src,sig){} for there you don't have any target you could bind
the object to.

>>> I think I prefer the name 'Qt::Proc', but the user would never use
>>> it directly so it doesn't matter too much.
>> Yeah, that's why I haven't called it Qt::Proc for the proxy doesn't
>> seem to fit the name "Proc" for it can't be used by developers inside
>> the apps as Qt-Version of ruby-procs.
> Ok, it needs more thought. I don't think 'Invocator' is a proper work - it 
> should either be 'Invocation' or 'Invoke'  or 'Invoker' as far as I know. So 
> Qt::InvokeBlock or Qt::BlockInvocation perhaps.

Yeah, I'm still not fluent in english. so maybe i just got the wrong name.
invoker sounds to me more like what i meant. But I don't mind if it is
called somehow different.

> Yes, I was thinking of the other case when there are three args, plus a block 
> and it should be invoked in the context of the last arg.
> 
> @button = KDE::PushButton.new(self)
> 
> class Foo < Qt::Object
>     def initialize
>         super
>         @button = KDE::PushButton.new(self)
>    end
> end
> 
> @other_button = Foo.new
> 
> Qt::Object.connect2Block(@button, SIGNAL('clicked()'), @other_button) {
>     @button.text = "Hi"
> }
> 
> Here I would expect it to set the text of the button in Foo class as the 
> target connected to the signal is an instance of Foo.

Ah, i see now the purpose of it.