Paul Rubin <no.email@nospam.invalid>:
> Marko Rauhamaa <ma...@pacujo.net> writes:
>> Stroustrup apparently has never had to deal with callbacks; his thick
>> books never made a mention of them last time I checked.
>
> C++ has function pointers just like C,
Et tu, Brute!
C's callbacks always use a void pointer for the "self reference." In C,
I can use void pointers and type casts idiomatically. In C++, type casts
are apostasy.
Qt gave up on C++ when it comes to callbacks ("signals") and went for an
apocryphal metacompiler.
> but more idiomatically you'd pass a class instance and the library
> would invoke some method on it.
Yes, that's what I ended up doing, defining a class for each callback
type:
struct ButtonPushListener {
virtual void buttonPush(int x, int y) = 0;
};
(Yes, "struct" and not "class"! Why?)
Typing all of that in was quite a chore. All because Stroustrup didn't
think of delegates (Delphi, C#, Python). C++'s method pointers are
ridiculous and useless, they should have been defined as delegates.
> There is also Boost::Coroutine which can get rid of the need for
> callbacks in some situations.
Boost is the world's biggest fig leaf.
Marko
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