Re: [gtk-list] Re: Signal and event management.

[Karl Nelson <kenelson ece ucdavis edu>]

Regarding Gtk--:

Gtk-- just uses templates to wrap the gtk+ signal connections.  The
reason for this is to allow typesafty of C++.  Basically, they
do nothing but provide a call and connect function while giving
the compiler a template to match arguments with so that type mismatches
are disallowed.
(templates are located in gtk--/src/build_sources)

The interactions of connections are described both ways.  
The gtk+ system can call a C++ function
through the proxy or a C++ function can call a gtk+ function.
When a signal is emitted from C++, it is dispatched to a C++ function, that
either calls a list of C and C++ functions (our signal system) or
calls the lower gtk+ signal model.  If a signal is emitted from gtk+ C
level, it will call a static function that calls into our layer.  All
of the Proxy code that you see there is to name the static functions
and proxies to gtk+ equivelents.  That is why the gensig preprocessor
builds the source of Gtk--.   

All of this is done at connect time...  We implement a new
connect that we use to decide whether it connects to the lower level
or stays in our C++ system.  We do not interrupt any of the calls of
gtk+ normally, other than to call the impl function.  See VDK if
you want to see a system that is more envasive to the signal system.
You may also want to look at WxGtk (I think), as theirs is a wrapper
that changes the hierachy.

Basically, ours is the opposite of your model where you wish to capture
all events and signals.   We capture nothing unless the user instructs a
connection to be made.  To do what you are describing, you may 
want instead take over the event loop and then channel the 
events to your signal dispatch system.  That why you get to 
initate the events to the gtk+ system.  You can then
reemit them to gtk+ for those events your system does not handle.  Then
you would also have to describe the interactions of your system with
signals emitted from gtk+ (such as button pressed).  (It is still 
a lot of work!)

I hope this helps.

--Karl