John Carter wrote:

> Can anyone think of a more sane word / phrase than "The class that it is 
> mixed in to"?
> 
> eg. Array is the class that Enumerable is mixed in to.
> 
> In particular has anyone devised a standard way of documenting / 
> enforcing the signature that "the class that it is mixed in to" must 
> conform to.

I have no fancy name for the inclusion target, but I have implemented 
stating interface requirements via contracts and automatically mixing in
modules when a class fulfills a contract.

It is available on http://ruby-contract.rubyforge.org/ -- it's an 
exploratory project which means you probably don't want it as a 
dependency right now -- but it also means I'm very curious about 
feedback and that it might help others to see new approaches to old 
problems.