On the richness of C++

[Walter Bright]

Edward Diener wrote:
> It is only a big deal in the sense that proving a single callback 
> signature or a single event signature, rather than two of each because 
> of the presumed need to support both delegates and function pointers, is 
> a big deal. In other words it is much cleaner to present a single 
> callable interface in a language, ala boost::function, Python callables, 
> C# delegates etc etc. The callback or event does not care if the 
> callable is a delegate or function pointer as long as the signature 
> matches, so it is a PITA if a language can not fold both into a single 
> callable concept. That is the issue and I think if you think about it 
> you will realize why it is better from both a clarity and ease of use 
> perspective to have a single callable representing both. There is no 
> sense in a language as rich as D to have to move backward from what 
> other other good languages are able to represent.

There's no reason you cannot write a template in D to do it - Andrei has 
done so in his std.algorithms code.