ZDoom

You can work around the lack of function pointers like early Java did: with an abstract “event handler” class, and concrete classes that override its method.

Alternatively, you could write a subclass of your button class, which overrides its “button clicked” method to perform the action.

Not going to happen.

So, I realise this probably isn't likely to happen, and there's probably some reason its impossible, but on the off-chance that it is doable, I might as well ask - it'd be nice to be able to store a reference to a function and call it from that reference. For example, I am creating a GUI system using the ZScript menus, and it seems like the most sane way to implement button commands would be through a function pointer that executes the function when the button is clicked.