Re: Binding Variables to Widgets

[muppet <scott asofyet org>]

On Jan 4, 2007, at 12:12 AM, Nik Ogura wrote:

> Forgive my noobishness, I'm coming from a Perl/Tk background.
>
> In Perl/Tk you can easily bind a variable to a widget, so that any
> changes to the widget text are automatically changed in the bound
> variable.
>
> Is this sort of thing possible in Gtk2-perl?  Or am I stuck doing
> $widget->set_text and $widget->get_text calls to do the same?
>
> Thank you in advance.

I second Emmanuele's recommendation of Glib::Object::tie_properties 
().  The thread introducing and debating the relative merits of this  
mechanism can be found here:

   http://mail.gnome.org/archives/gtk-perl-list/2003-October/ 
msg00201.html

Of course, you could just use the object property interface directly:

   ($foo, $bar, $baz) = $object->get (qw/foo bar baz/);
   $object->set (foo => $new_foo, bar => $new_bar, baz => $new_baz);
   $object->signal_connect ('notify::foo' => \&on_foo_changed);


However, in the spirit of TIMTOWDI and full disclosure, this topic  
has been broached before.  Bjarne Steinsbo created a class called  
Gtk2::BindVariable, which is discussed in the thread "A little tie  
magic", which starts here:

   http://mail.gnome.org/archives/gtk-perl-list/2003-December/ 
msg00039.html

We did not include that in the distribution for a few reasons:  
different developers had style disagreements over it, we already had  
Glib::Object::tie_properties(), and about this time we realized that  
including lots of pure-perl code with the xs-only bindings was  
starting to cause maintenance grief.


Take-home message --- gtk2-perl provides you the full gtk2 API, with  
a few spartan niceties, but doesn't intend to go beyond that.  If you  
want to layer your own convenience stuff atop that, please do, and  
share it on CPAN.