Re: [boost] C++11 Metaprogramming

Subject: Re: [boost] C++11 Metaprogramming
From: Dave Abrahams (dave_at_[hidden])
Date: 2012-04-03 13:39:05

on Sun Apr 01 2012, Abel Sinkovics <abel-AT-elte.hu> wrote:

> Hi,
>
>> On 01.04.2012, at 21:01, Mathias Gaunard wrote:
>>
>>> On 04/01/2012 06:36 PM, Eric Niebler wrote:
>>>> On 3/31/2012 7:12 PM, Dave Abrahams wrote:
>>>>> Hi All,
>>>>>
>>>>> I am on the C++Now 2012 schedule giving a talk on metaprogramming in
>>>>> C++11, which is really just supposed to be an overview of the state of
>>>>> the art.  I am just at the beginnings of my research for this
>>>>> presentation, having learned a few things and done a few experiments,
>>>>> and it seemed to me foolish not to ask the Boost community for its
>>>>> insights.  I'm sure y'all have come up with many neat tricks and
>>>>> techniques.  If you'd care to share them here, that would be much
>>>>> appreciated.
>>>> I recall a discussion about processing string literals at compile time
>>>> using user-defined literals. Surely that counts.
>>> Not sure if they didn't remove that feature in the end.
>> They did. The template<char... Chars> operator "" syntax is only
>> valid for integer (and I think floating point) literals according to
>> the FDIS.
>
> It was me writing about it and we ended up using constexpr functions
> to achieve the same goal - I sent our solution to this list as
> well. One can write:
>
> MPLLIBS_STRING("This is cool")
>
> which expands to the definition of a boost::mpl::string. To make usage
> of it easier, we created an "alias" for MPLLIBS_STRING called _S, so
> one could write:
>
> _S("This is cool")
>
> Our implementation can be found here:
> https://github.com/sabel83/mpllibs/blob/master/mpllibs/metaparse/string.hpp
> It is an important part of the Mpllibs/Metaparse library I'm going to
> present on C++Now.
>
> It is a C++11-only solution for template metaprogramming, so I think
> it could be a great addition to an overview about that.

Definitely. An excellent point.
I don't suppose one can #include a file inside a string literal somehow? ;-)

_S("
#include "metaprogram"
")

-- 
Dave Abrahams
BoostPro Computing
http://www.boostpro.com