[boost] Re: Variant Library: visitation algorithm

From: Gennadiy Rozental (gennadiy.rozental_at_[hidden])
Date: 2003-04-05 00:29:43

> >       case MAX_WITCH:
> >            visitor( Typelist[MAX_WITCH](storage) );
> >            break;
> >       }
> > }
>
> Your pseudo-code is misleading. There is no "MAX_WHICH" available to the
> preprocessor when MPL-sequences are given because there is no theoretical
> upper limit on the size of a type-sequence.

1. There is "theoretical" limits for the size of MPL sequences. See MPL docs
(BOOST_MPL_LIMIT_LIST_SIZE for list)
2. You could limit variant support only for lists that does not exceed your
own limit BOOST_VARIANT_LIMIT_TYPES.
3. You could choose/define any other arbitrary limit (it should probably
exceed limits mentioned in items 1 and 2)

All you need once you chose the limit is to add default clause to above
switch statement with static assert in it. So I believe my code is perfectly
implementable.

Gennadiy.