C++ and Beyond 2012: Alexandrescu, Meyers, and Sutter - Ask Us Anything

Excellent Q&A! Thanks Charles/Channel 9 and C++ gurus.

Good to see these gentlemen back with another excellent session. Thank you Charles for bring us this!

That said, based on the content of this session, next year I suggest that there are two conferences: 'C++ & Beyond 2013' and 'Auto & Beyond 2013'... Amazed at just how much time 'auto' was given

Agree with dot_tom. Thanks for sharing!

I didn't know there was so much to say about auto...

I guess it's up to tooling to show you what the type actually is.

Thanks for this.  Will there be more C++ and Beyond 2012 posted?  Thanks.

10 hours ago, Charles wrote

@AceHack: Indeed. Slowly but surely. Stay tuned!

C

Great !

Early in the video, Herb Sutter mentions some email address that seems to be '...@cpp.org'. Was that it? Is it correct? The cpp.org site seems not to be related to C++ at all.

That would be std-discussion@isocpp.org

https://groups.google.com/a/isocpp.org/group/std-discussion

https://twitter.com/isocpp

http://s151836.gridserver.com/

So I guess this is the secret 'special announcement' of Herb Sutter ???

The video files seem to be corrupted. High Quality WMV size is shown as 3.5GB but download terminates at around 103 MB. Similarly, High Quality MP4 is advertised as 696MB but terminates at 103MB on download. Can you please fix these ?

Thanks in advance
Dileep Balakrishnan

This is really fantastic!

Where do we get to see the concepts getting implemented strictly using C++11 language and library features? We will prefer a simple library to start using it right away.

We were referring to the famous paper "A Concept Design for the STL" by Dr. Bjarne Stroustrup et al., which inspired us to dive into Origin C++ Libraries, which is an implementation using C++11. We ended up collating the ideas with our experiments to put these into work in our book : "Foundation of Algorithms in C++11, Volume 1 : Using And Extending C++11, Boost And Beyond". But to go further, we need a complete set-up for C++11 concepts and Origin libraries are still very incomplete and experimental in nature.Can someone point to a library, which is put to practice? Any pointer will be very helpful.


To be clear, we do not mean "C++ Concepts & Axioms" which (as originally proposed) cannot be fully implemented as a library feature.


For example, the paper "A Concept Design of STL" proposes the following interface for the STL Algorithm "std::copy_backward":

template<BidirectionalIterator I, BidirectionalIterator Out>
requires IndirectlyCopyable<I, Out> Out copy_backward(I first, I last, Out result);



which cannot be implemented using just library features.

So we reduced it to look like the following :


template<typename I, typename I>
requires<IndirectlyCopyable<I, Out>() && Bidirectional_Iterator<I>()>
Out copy_backward(I first, I last, Out result);



This we were able to get it easily using sfinae feature : enable_if. But we are looking for something like this in a form of a full blown C++11 library.


Using template alias and sfinae, simulation of requires may look like :

#include <type_traits>
template <bool Condition, typename T = void>
using requires = typename std::enable_if<Condition, T>::type;



And the Conditions being passed to requires can be simulated using the language feature "constexpr" like:

template <typename I, typename Out>
constexpr bool IndirectlyCopyable() { ...}

template <typename I>
constexpr bool Bidirectional_Iterator() { ...}



So, all we are looking for a C++11 library, which fully implement C++11 Algorithms using Concepts as part of algorithm's interface as in :


template<typename I, typename I>
requires<IndirectlyCopyable<I, Out>() && Bidirectional_Iterator<I>()>
Out copy_backward(I first, I last, Out result);



or

template<typename I, typename I>
auto copy_backward(I first, I last, Out result)
-> requires<IndirectlyCopyable<I, Out>() && Bidirectional_Iterator<I>(), Out>;



or something similar. Origin C++ library has similar components in place, but it is still a work in progress. Boost.Contract(Contract++) takes a different approach to simulate the above.

Does any one know of any such library in use?

Thanks a lot in advance.

Cheers,
Algocoders
http://www.algocoders.com

Thanks for the post. Will be waiting for some more..

Thanks
Srikanth Kanchari