From: Thorsten Ottosen (nesotto_at_[hidden])
Date: 2004-03-04 03:29:38
"David Turner" <dkturner_at_[hidden]> wrote in message
> Thorsten wrote:
> > "David Turner" <dkturner_at_[hidden]> wrote in message
> > news:30053.165.165.239.17.1078382983.squirrel_at_webmail.telkomsa.net...
> > [snip]
> >> The only real problem with "why not" is that gui widgets have shallow
> >> copy
> >> semantics.
> > And why is that a problem?
> Because it's surprising to the user (I think).
more surprising than hiding the type of window?
> More to the point, there is a very real problem with creating popup
> windows. Remember that the window acts as a factory for all other
> widgets, including popup (child) windows.
Hm...maybe I don't understand why it has to be that way?
> If I were to use the "why not"
> syntax, I would have to pass in the owner window as the first parameter of
> the constructor, as in:
> window w;
> button b(w, "Click here");
why can't we say
w.add( button( "Click me" ) ); (*)
window.add( new button( "Click me" ) );
(*) I can imagine how this could work with a clonable class hierarchy. It
must be possible for an object to
register itself as a child of a parent window within the w.add() function.
That function could first create
a clone heap-allocated of the argument (to get polymorphism) and then add
that pointer to its list of children.
Boost list run by bdawes at acm.org, gregod at cs.rpi.edu, cpdaniel at pacbell.net, john at johnmaddock.co.uk