Re: [boost] [array] compile-time checked access

Subject: Re: [boost] [array] compile-time checked access
From: Jeffrey Lee Hellrung, Jr. (jeffrey.hellrung_at_[hidden])
Date: 2012-11-05 09:31:29

On Mon, Nov 5, 2012 at 6:02 AM, Tobias Loew <Tobias.Loew_at_[hidden]> wrote:

> I used the "raw"-tag to quote the code. Here is it again without the tags:
>
> ...
> So, code like
>
>     boost::array<int,2> test;
>     test[2] = 1;
>     test[-1] = 1;
>
>
> compiles without warnings or erros.
> Now, adding the following functions to array
>
>         template<size_type i>
>         reference at()
>         {
>             BOOST_STATIC_ASSERT( (i < N) );
>             return elems[i];
>         }
>
>         template<size_type i>
>         const_reference at() const
>         {
>             BOOST_STATIC_ASSERT( (i < N) );
>             return elems[i];
>         }
>
>
> would make it possible to write
>
>     boost::array<int,2> test;
>     test.at<2> = 1;
>     test.at<-1> = 1;
>
>
> which results in the expected error messages.
>

You can try to use boost::fusion::at_c<N>(test), but not sure if it
actually has a static assertion. See

http://www.boost.org/doc/libs/1_51_0/libs/fusion/doc/html/fusion/sequence/intrinsic/functions/at_c.html
http://www.boost.org/doc/libs/1_51_0/libs/fusion/doc/html/fusion/adapted/boost__array.html

- Jeff