Communicating between in and out contracts

[Andrei Alexandrescu]

Jason House wrote:
> if fun or gun is impure, then they should not be callable by the
> contracts. Because of that, order is irrelevant.

1. Restricting calls to pure functions is sensible, but was deemed too 
restrictive.

2. Even so, there's difficulty on what to cache. The amount cached may 
depend on both the old and new object (in my example it only depends on 
the old object).

3. There's too much hidden work and too much smarts involved. I just 
don't think that's a feasible solution with what we know and have right now.


Andrei