Replace CRTP with Concepts -- Sandor Dargo

This article explores how C++20 concepts can replace CRTP when implementing static interfaces for a family of classes. By leveraging concepts, we achieve cleaner, more readable, and less error-prone codeΓÇöprovided you have access to C++20.

Replace CRTP with Concepts

by Sandor Dargo

From the article:

In my Meeting C++ 2024 trip report, among my favourite ideas I mentioned Klaus Iglberger’s talk where he mentioned the possibility of replacing the curiously returning template pattern with the help of class tagging and concepts.

Class tagging might mean different things in different contexts, or at least might be implemented in different ways. The end goal is to mark, in other words, tag classes or functions to be used in certain contexts, with certain algorithms. As you’ll see, in our case it’ll also be a tool to prevent duck typing.

We are going to see an example implementation of a static interface with CRTP with a couple of different derived classes, then weΓÇÖll see the implementation without CRTP.

The CRTP solution

With the static interface, we are creating a static family of types. There is no need for dynamic polymorphism to share the same interface. ItΓÇÖs still granted through a base class, which is a template taking the deriving class as a parameter.

 

 

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