Re: [boost] [type_at] Variadic template utility

Subject: Re: [boost] [type_at] Variadic template utility
From: Robert Jones (robertgbjones_at_[hidden])
Date: 2011-05-26 04:53:52

On Thu, May 26, 2011 at 8:34 AM, tymofey <tymofey_at_[hidden]> wrote:

> While experimenting with varidic templates of the upcoming standard i
> discovered that quite often one would need to extract a type from parameter
> pack at specified position. While the task is trivial it would be quite
> handy to have a ready tool for this purpose, rather that specifying one
> yourself every time.
>
> You can find source code consisting of a single header at
> Vault/Utilities/type_at.hpp
>
> The usage is simple:
>
>    boost::type_at<index, some_type_0, some_type_1, some_type_2,
> some_type_n>::type
>
> corresponds to some_type_index where index is in range [0..n]. For example:
>
>    boost::type_at<2, int, float, char, long>::type
>
> corresponds to char.
>
>
Forgive me if I'm missing the point, but isn't this essentially Boost.MPL's
'at' metafunction?

- Rob.