YesOrNo: useful idiom helper or wanking?

[Andrej Mitrovic]

Also, I would rather name this template "choice". Maybe if people got
used to this word they would understand it when they see it in the
documentation before a function definition. E.g.:

http://codepad.org/9mrL6MOG or if the site is down:
https://gist.github.com/913926

Otherwise I have no idea how you can put a new type definition inside
of a function parameter and make it public? I'm kind of confused
here..