experimental

Implementing the spaceship operator for optional—Barry Revzin

The future implementation?

Implementing the spaceship operator for optional

by Barry Revzin

From the article:

Last week, the C++ Standards Committee added operator<=>, known as the spaceship operator, to the working draft for what will eventually become C++20. This is an exciting new language feature for two reasons: it allows you to write one function to do all your comparisons where you used to have to write six, and it also allows you to write zero functions — just declare the operator as defaulted and the compiler will do all the work for you! Exciting times...

Ranges, Coroutines, and React: Early Musings on the Future of Async in C++—Eric Niebler

Eric Niebler shares his thoughts about the interaction of ranges and co-routines in his recent blog post.

Ranges, Coroutines, and React: Early Musings on the Future of Async in C++

by Eric Niebler

From the article:

Another way to look at this is that synchronous ranges are an example of a pull-based interface: the user extracts elements from the range and processes them one at a time. Asynchronous ranges, on the other hand, represent more of a push-based model: things happen when data shows up, whenever that may be. This is akin to the reactive style of programming.

By using ranges and coroutines together, we unify push and pull based idioms into a consistent, functional style of programming. And that’s going to be important, I think.

Trip Report: C++ Standards Meeting in Toronto, July 2017—Botond Ballo

Another report:

Trip Report: C++ Standards Meeting in Toronto, July 2017

by Botond Ballo

From the article:

A couple of weeks ago I attended a meeting of the ISO C++ Standards Committee (also known as WG21) in Toronto, Canada (which, incidentally, is where I’m based). This was the second committee meeting in 2017; you can find my reports on previous meetings here (November 2016, Issaquah) and here (February 2017, Kona). These reports, particularly the Kona one, provide useful context for this post.

CppCon 2016: Iterator Haiku—Casey Carter

Have you registered for CppCon 2017 in September? Don’t delay – Registration is open now.

While we wait for this year’s event, we’re featuring videos of some of the 100+ talks from CppCon 2016 for you to enjoy. Here is today’s feature:

Iterator Haiku

by Casey Carter

(watch on YouTube) (watch on Channel 9)

Summary of the talk:

Iterator Haiku: How five iterator categories blossomed into seven, and Sentinels trimmed them back to five again. Recently proposed changes to the ranges TS distill its seven iterator categories back to five without sacrificing any expressive power. Removing operations that are extraneous in the Sentinel world eliminates a potential source of programming errors.

Yielding Generators—Kirit Sælensminde

The series continue!

Yielding Generators

by Kirit Sælensminde

From the article:

We've seen how the promise_type together with the coroutine return type handles the interactions between the caller and the coroutine itself.

Our target is to be able to do something pretty simple:

generator count() {
    std::cout << "Going to yield 1" << std::endl;
    co_yield 1;
    std::cout << "Going to yield 2" << std::endl;
    co_yield 2;
    std::cout << "Going to yield 3" << std::endl;
    co_yield 3;
    std::cout << "count() is done" << std::endl;
}