How to Turn a Hierarchy of Virtual Methods into a CRTP

by Jonathan Boccara

So let’s see how to implement static polymorphism in the above code. This question can be split into two parts:

• How to replace virtual methods by a CRTP,
• How to make a CRTP inherit from another CRTP...

Error Handling and std::optional

by Bartlomiej Filipek

In my last two posts in the C++17 STL series, I covered how to use std::optional. This wrapper type (also called “vocabulary type”) is handy when you’d like to express that something is ‘nullable’ and might be ‘empty’. For example, you can return std::nullopt to indicate that the code generated an error… but it this the best choice?

Declarative Functional APIs – A.K.A. Abusing Lambda Parameters

by Philippe Groarke

Functional APIs are a joy to work with. Not only do they help eliminate certain bug categories, but they tend to be very flexible and reusable. Today I present a technique that has emerged while I was simplifying some lambda based APIs. C++17 makes template meta-programming much more palatable, I dare not imagine what this would look like in C++11...

Should Span Be Regular?

by Barry Revzin

In my last post, I talked about the concept of Westie types (yes, I am trying to make this happen), what Regular means, and which of them are Regular. I went through an explanation for why means for span is not Regular and potentially why it should be. After lots of resulting conversations with several people (thanks Zach Laine, Nicole Mazzuca, Eric Niebler, John Shaw, Tim Song), I thought it was necessary to write a follow up with more details and more argument...

C++: On Using int*_t as Overload and Template Parameters

by No Bugs" Hare

In C++, there is a concept of “two types being the same”. I am a Big Fan(tm) of this concept and find it very useful, but sometimes it starts causing trouble. Here is one such example – and a way I am using to deal with it...

Stupid C++ namespace tricks

by Raymond Chen

These tricks may be obvious, but at least I'm going to write them down...

Rvalues redefined

by Andrzej Krzemieński

In this post we will explore what I consider the most significant language change in C++17. I call it the most significant because it changes the way you design your resource-managing types and how you think about initialization. It is often called “guaranteed copy elision”, but I will not use that name (except for this single time) because it does not reflect what this feature is. C++ has completely changed the meaning of rvalue (actually, prvalue)...

std::accumulate vs. std::reduce

by Simon Brand

std::accumulate has been a part of the standard library since C++98. It provides a way to fold a binary operation (such as addition) over an iterator range, resulting in a single value. std::reduce was added in C++17 and looks remarkably similar. This post will explain the difference between the two and when to use one or the other...

Overload: Build a Variant Visitor on the Fly

by Arne Mertz

Having written about std::variant and std::visit last week, it’s time to string together some modern C++ features to build a naive basic implementation of overload, a proposed C++ feature...

How to Make SFINAE Pretty – Part 2: the Hidden Beauty of SFINAE

by Jonathan Boccara

As we’ve seen in How to Make SFINAE Pretty – Part 1: What SFINAE Brings to Code, SFINAE in code is as pretty as a windmill in a field. That is, not very pretty.

But like a windmill, it’s useful. SFINAE helps deactivate a piece of template code depending on a condition, and that can be very convenient...