Drag and drop on NS?

[Po Lu]

Does anyone with experience with Nextstep APIs (either GNUstep or Cocoa)
want to step up to implement drag-and-drop on that platform?

You will have to implement `x-begin-drag', which will probably involve
creating a pasteboard visible to Lisp as `XdndSelection' in nsselect.m,
and passing that pasteboard to [NSView dragImage].  See the
implementations on X and Haiku for more details.

I didn't figure out some details: the function has to be synchronous
(i.e. it should only return when the drop completes or was canceled),
and it has to take into account different selection targets, such as
STRING and text/uri-list.

Thanks.