Re: [boost] About all these metaprogramming libraries

Subject: Re: [boost] About all these metaprogramming libraries
From: Bruno Dutra (brunocodutra_at_[hidden])
Date: 2017-03-19 19:33:49

On Sun, Mar 19, 2017 at 8:09 PM, Peter Dimov via Boost <
boost_at_[hidden]> wrote:

> Oswin Krause wrote:
>
> For me the biggest question is: will it work natively with mpl::vector?
>>
>
> Not very well at the moment; mpl::vector<int, void, float> is a list of
> fixed size 20, whereas mpl::vector<int, void, float>::type is of size 3,
> but still fixed. It will only work with algorithms that don't need to
> change the size of the list.
>
> It would be possible in principle to make the algorithms take mpl::vector
> and return mp_list, I suppose.
>

You forgot to take into account that algorithms such as mpl::insert and
mpl::erase return proxies that inherit from vectors and don't expose the
elements in their types signatures, while being themselves valid instances
of a Vector. This is the real deal breaker.