The question isn't so much what you can use to duplicate that technique of mashing code symbols together, but finding out why you thought you'd need it in the first place, and then decide on an appropriate, modern way to solve it.
That said, since the example seems to be about a 'simplified' set functionality, let me point you to the
__declspec(property)
statement that VisualStudio provides. I'm not a big fan, in part because it's VS-specific, but maybe it helps you achieve something similar:
https://msdn.microsoft.com/en-us/library/yhfk0thd%28v=vs.120%29.aspx[
^]