Re: [Boost-users] [mpl] erase_key confusion

From: Gottlob Frege (gottlobfrege_at_[hidden])
Date: 2007-03-23 13:02:37

On 3/23/07, Scott Meyers <usenet_at_[hidden]> wrote:
>
> Any other suggestions?
>
> Thanks,
>
> Scott
>

Do you know what the bug in mpl is?

we have, essentially:

        : eval_if<
              has_key_impl<aux::set_tag>::apply<Set,T>
            , eval_if<
                  is_same< T,typename Set::item_type_ >
                , base<Set>
                , identity< s_mask<T,Set> >
                >
            , identity<Set>
            >

Can we assume kas_key_impl works? I would hope so, else mpl::set is a
bit useless.
The if (is_same) then base<Set> is pretty simple,
so I suspect it is the s_mask<T, Set> that is causing problems.

And, unfortunately, although staring for the usual requisite hour,
s_mask, although small (or because it is small), makes no sense to me.

In particular, I thought it would have a 'type' typedef'd somewhere in
it, but I don't see it.

Tony