7,8c7
< X = (:-(...)).
< 
---
> X = (p :- retbool, inc, assert(X), fail).
10a10,44
> > 
> _A: p :-
>         _B: (retbool,
>         inc,
>         assert((_A :-
>         _B)),
>         fail).
> 
> *** Yes
> > 
> *** Yes
> > 
> *** Yes
> > 
> _A: p :-
>         _B: (retbool,
>         inc,
>         assert((_A :-
>         _B)),
>         fail).
> p :-
>         fail.
> 
> *** Yes
> > 
> *** Yes
> > 
> *** No
> > 
> % 'p' is a user-defined predicate with an empty definition.
> 
> dynamic(count)?
> count -> 999.
> 
> *** Yes
