Re: Pointers to member functions are NOT useless
On Jul 24, 4:36 pm, =D6=F6 Tiib <oot...@hot.ee> wrote:
On 24 juuli, 18:10, "Francesco S. Carta" <entul...@gmail.com> wrote:
I'd like to ask you if you can come up with some real life examples
where you have taken advantage of pointers to member functions -
unfortunately, being an hobbyist, my best example comes straight from
the top of my head ;-)
For loosely coupling something.
For example typical silly observer pattern implementation expects my
observer to have virtual handleEvent(Observed& ref) method. Virtual
from IObserver base interface. Why? Looks like direct translation from
java with no brain applied. I can just boost:bind any member function
as an observer functor. Only limit is that it has to have unique
member function name in class (may not have overloads).
For boost::bind. (Actually, there's no requirement that there
be no overloads, but if there are overloads, you have to
explicitly select which one to use, which is a little bit
awkward.) Earlier GUI implementations simply took a pointer to
member function directly.
That way i need no useless interface base classes and virtuals and lot
of other bloat and nuisance usually connected to loose coupling
patterns. Patterns look like too tightly coupled after such thing
applied for my taste. The calling and binding of member function
pointers should be templatized to not confuse novices. Also i usually
suggest to consider boost::signals2 first when someone needs
multithreaded version of such.
Earlier GUI frameworks used the pattern you suggest. It was
quickly abandonned for a more explicit base interface class; the
explicit interface results in significantly more readable, more
maintainable code.
--
James Kanze