in reply to merge two simple data structures

Abigail-II provided the solution. What I do wonder about however is why you want to do so? I know I've wished for something similar sometimes in the past, but in retrospect I found that every single one of these times was due to a misguided approach. If you want to, maybe you could explain your reasoning and see if someone can't come up with a better approach to this.

Makeshifts last the longest.