Re: [boost] Re: safe_bool alternative?

From: Peter Dimov (pdimov_at_[hidden])
Date: 2003-11-25 10:51:50

Joel de Guzman wrote:
>
> IIUC, what you mean is that we do not have to review something like
> that. Ok, but it would still be good to have a single implementation.
> Spirit uses:
>
>     struct safe_bool_impl
>     {
>         int* dummy;
>     };
>
>     typedef int* safe_bool_impl::*safe_bool;
>
>     inline safe_bool
>     make_safe_bool(bool cond)
>     {
>         return cond ? &safe_bool_impl::dummy : 0;
>     }
>
> and it is used all throughout.

Then you should call it unsafe_bool since having a conversion to it permits
comparisons between unrelated types.