[Kde-bindings] disconnecting a block in qtruby4

[Stefano Crocco]

In qtruby4, you can connect a signal to a block, but is there a way to 
disconnect the signal afterwards? One way, of course would be to use 
disconnect passing only the name of the signal, but that would disconnect all 
slots/block/signals connected to it. For example:

btn1 = Qt::PushButton.new 
btn2 = Qt::PushButton.new
btn1.connect(SIGNAL('clicked()')){puts "btn1 clicked"}
Qt::Object.connect btn1, SIGNAL('clicked()'), btn2, SIGNAL('clicked()')

If I then do:

btn1.disconnect SIGNAL('clicked()')

which, as far as I know, it's the only way to disconnect the block from the 
clicked() signal of btn1, I would also disconnect the clicked() signal of 
btn2, which may not be what I want.

Is there another way to do this? The reason I'm asking this is that I'm in a 
situation like the one in the following piece of code:

require 'Qt4'

app = Qt::Application.new []
b1 = Qt::PushButton.new('Change label')
b2 = Qt::PushButton.new('Delete label')
l = Qt::Label.new 'Test'
b1.connect(SIGNAL('clicked()')){l.text = "TEST"}
b1.show
b2.connect(SIGNAL('clicked()')){l.dispose}
b2.show
l.show
app.exec

Here there are two push buttons and one label. One button changes the text of 
the label; the other disposes of the label. If I press the second button, then 
the first, I get a crash, because the label doesn't exist anymore, but the 
block which changes its text is still called and there's no way to disconnect 
it (of course, the real situation is much more complex, so simple solutions 
which would work here, such as calling b1.disconnect( SIGNAL('clicked()')) 
from the block connected to b2 wouldn't be availlable to me).

Looking at the code for Qt::Internal.signal_connect, which (according to the 
comments) should manage the connections with blocks, this kind of connections 
actually connect an internal Qt::SignalBlockInvocation object to the signal 
and that object, I guess, calls the signal in one of its slots. If the connect 
method returned the Qt::SignalBlockInvocation object, it could be used as 
argument to disconnect to break the connection. Could it be done? Or is there 
another way to do what I'm asking?

On a related subject, is there a reason for which there's a Qt::Object.connect 
class method (corresponding to the static C++ method), but not a corresponding 
Qt::Object.disconnect class method?

Thanks in advance

Stefano