mutually-recursive types and an old puzzle

[Joe Buck]

On Wed, Jun 30, 2004 at 02:43:06AM +0200, Gabriel Dos Reis wrote:
> Yes, C does not has a fixpoint combinator.  C++ does.
> 
> struct T {
>    T operator()() const { return T(); }
> };

That doesn't quite suffice, but it looks like it can be made to do so (we
need a set of function-objects that can return references to each other).