>From what I can tell std.signal is designed around the idea that an entire class acts as a signal emitter, without the ability to write multiple signals within one class and making arbitrary connections between signals and slots.
If you actually read the full paper it links to: http://www.elpauer.org/stuff/a_deeper_look_at_signals_and_slots.pdf you'll see that the idea of signals and slots is to avoid writing specialized signal classes, and instead just use member functions as signal emitters. I don't see why we can't have something as good or even better than Qt's and Boost's signals and slots implementations. I admit I haven't had a look at the other implementations linked from the std.signals page yet, so maybe there's some better implementations out there. But from a current standpoint it looks to me like std.signal is a good candidate for a revamp.
