Re: gtk.Window() and accelerator

Marcus Habermehl wrote:
> > Please, remember that callbacks assigned in connect_group must return 
> > True.  Otherwise GTK+ will segfault sooner or later.  It is probably 
> > irrelevant to this example as it only calls gtk.main_quit(), but if you 
> > want to do other things in callback it must return some value.
>
>
> Is the "i" the returning value in your example?

No, it's the code from my program, Snakememory, and I slightly modified 
it. In my program it is used in loop to create Alt-[0-5] accelerators 
for indicating response quality.  Requirement of returning boolean value 
from accelerator callback is the requirement of GTK+ library.  It will 
segfault otherwise at some random place (which is probably bad as 
extension modules shouldn't generate SIGSEGVs).

> Because there are some things in your example that I not understand.
>
> key, modifier = gtk.accelerator_parse('<Alt>%d' % i)
>
> Why %d instead d and what is % i? 

Here's the real unmodified code from my program:
 accelgroup = gtk.AccelGroup()
 for i in range(6):
     key, modifier = gtk.accelerator_parse('<Alt>%d' % i)
     accelgroup.connect_group(key, modifier, gtk.ACCEL_VISIBLE,
                                       lambda a,b,c,d,i=i: 
self.assess_quality(i))
 self.view.recall_card_window.add_accel_group(accelgroup)

This loop creates callbacks for key sequences Alt-0, Alt-1, ..., Alt-5
"'<Alt>%d' % i" is a usual string interploation.

> accelgroup.connect_group(key, modifier, gtk.ACCEL_VISIBLE, lambda a,b,c,d,i=i: 
> self.assess_quality(i))
>
> Are a,b,c,d,i widgets in your script? And why =i? I supposing
> self.assess_quality(i) is a function from you that returns the needed
> value for GTK+. I'm right?

a,b,c,d are GTK+ arguments for callback, see the documentation. I've 
named them a,b,c,d because I don't use them and therefore lazy to type 
proper names. "i=i" is used because otherwise "i" variable in all lambda 
callbacks will equal to the final value of "i" in the loop (5).  See PEP 
227 (nested scopes). self.assess_quality() does some computations using 
the user feedback and returns True.  You can do whatever you want in 
your callback, the only requirement is to return true value for GTK+.
Eugene

--
Email: eugene @ renice.org   Homepage: http://eugene.renice.org

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