Advantages of Concepts

More generally, what are the advantages of concepts?

Advantages

• Requirements for template parameters are part of the interface.

• The overloading of functions and specialization of class templates can be based on concepts.

• Concepts can be used for function templates, class templates, and generic member functions of classes or class templates.

• You get improved error messages because the compiler compares the requirements of the template parameters with the given template arguments.

• You can use predefined concepts or define your own.

• The usage of auto and concepts is unified. Instead of auto, you can use a concept.

• If a function declaration uses a concept, it automatically becomes a function template. Writing function templates is, therefore, as easy as writing a function.

The long, long history

The first time I heard about concepts was around 2005 - 2006. They reminded me of Haskell type classes. Type classes in Haskell are interfaces for similar types. Here is a part of Haskell’s type classes hierarchy: