return in loop for ?

[Duncan Booth]

Steven D'Aprano wrote:

>> While outwardly they apear to offer a technique for making software
>> more reliable there are two shortcomings I'm leery of. First, no
>> verification program can verify itself; 
> 
> That's not a problem if there exists a verification program A which
> can't verify itself but can verify program B, which in turn also can't
> verify itself but will verify program A.
> 
That is logically equivalent to the first case, so it doesn't get you 
anywhere. (Just combine A and B into a single program which invokes A 
unless the input is A when it invokes B instead.)