Re: [OT?] libglade, guile-gtk and glade-xml-signal-autoconnect

[Bill Gribble]

On Wed, 2002-01-30 at 08:58, Brett Viren wrote:
> But, maybe you mean that the (glade-xml-signal-autoconnect ...) simply
> doesn't look through "scheme space" for symbols (which is what I
> feared).

That's what I'm saying.  glade-xml-signal-autoconnect is just a wrapper
that calls glade_xml_signal_autoconnect, which means that only C
function bindings are looked for. 

>  > 
>  >   (gtk-signal-connect 
>  >     widget "clicked"
>  >     (lambda () 
>  >       (simple-format #t "widget ~A was clicked.\n" widget)))
>  > 
>  > I find the current behavior convenient, because I like using anonymous
>  > functions as signal handlers.
> 
> Yes, I agree.  Many handlers don't/shouldn't care about what widget
> triggered them.

That's not really what I meant.  The example is intended to demonstrate
that most handlers *do* want to know what widget triggered them, and
that the current guile-gtk bindings supports this nicely within the
idiom of anonymous functions as callbacks.  


> 
>  > What would happen if you used a generic Scheme function-caller as the
>  > signal handler, and put a literal C string with quotes in the "data"
>  > field?  the string could be the Scheme function name.  This might not
>  > work at all, I'm just thinking out loud. 
> 
> Or how about defining the callbacks in a scope that can see the
> widgets they need.  Ie:

Sure, that's fine.  But you can't really do the lookup from a string to
a procedure unless the lookup function itself is in the same lexical
scope as the procedure.  that generally means that if you are depending
on a global function to do the callback autoconnect, the callbacks have
to be top-level functions, which makes it harder to do that kind of
trick.

b.g.