Re: Handling multiple selections in a Gtk::TreeView

[Matthew Walton <matthew alledora co uk>]

Murray Cumming wrote:
> > When working with multiple selections, I find
> > myself using get_selected_rows() much more frequently, to get a vector
> > or list of selected rows, then iterating over that with a for loop. I
> > might use selected_foreach more if C++ had anonymous functions.
>
>
> Yes, I think that get_selected_rows() was added sometime after
> selected_foreach(), because it was more convenient.
>
> I don't understand the comment about C++ not having anonymous functions.
> Maybe that's C# terminology.

I'm not sure if C# supports anonymous functions, I was thinking more of 
Python, Haskell and Perl (Python and Haskell call them 'lambda 
functions'). They seem to be a feature of languages with late binding 
and functional languages (where functions aren't really distinct from 
values) rather than the more static kind of language, of which C++ is an 
example.

I don't know their exact syntax, but I believe that Gtk-Perl allows you 
to use anonymous subs as callbacks. If they have selected_foreach, that 
might look like this:

$treestore->selected_foreach(sub {
  # do something here
});

They're very handy, but don't really fit in the C++ mold. I suspect 
things like selected_foreach would be more useful if they did.

> > Really,
> > which one to use depends on what you want to do - sometimes
> > selected_foreach is more convenient.
>
>
> Actually, I can't think of a case when it is right now. If you think of
> one, let's document it.

To be honest, neither can I...