assert() vs. enforce(), invariant() vs. ... ?

[Joseph Rushton Wakeling]

On 29/08/13 21:44, Jacob Carlborg wrote:
> It is a proxy. What's the point of a proxy if not to add some additional
> functionality.

No, I mean std.typecons.Proxy:
http://dlang.org/phobos/std_typecons.html#.Proxy

The point is that std.typecons.Proxy _just_ wraps the underlying type; it 
doesn't, so far as I can see, allow you to define extra functionality that must 
be implemented whenever a public method of the underlying type is called.