Hairy Pixels <generic...@gmail.com> schrieb am Sa., 4. Nov. 2023, 15:48:
> > > > On Nov 4, 2023, at 4:22 PM, Sven Barth <pascaldra...@googlemail.com> > wrote: > > > > Then don't assign them every "frame". If you just keep them around then > they aren't more expensive than a virtual method call. > > And any other mechanism would involve the heap as well, because that's > how anonymous functions that capture variables work and thus anything that > wants to store them must play by the same rules. There won't be any changes > there. > > > > The need for a universal function pointer type really isn't about the > function references even though they work for that, albeit with unneeded > overhead. > > Lets say you have a sort function which takes a compare callback > parameter. You can make the callback type "is nested" which works on global > and nested/anonymous functions but not methods. What if the user wants to > provide the compare function as a method because they're calling it in a > class which shares the code elsewhere? As the writer of the function you'd > need to make 2 versions of the function, one "is nested" and "of object". > > The writer of the sort function shouldn't need to know what kind of > function it will be passed, just that a comparison callback is provided, > right? > Then you simply make the callback function type a function reference and be done. The user can pass in any kind of function they want and *nearly* every type of function-like pointer. And if you're really worried about performance when providing such a class then simply provide overloads woth different function-like pointer types, the compiler will pick the most suitable one then. It's really not that hard as an implementer of a class. Regards, Sven >
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