Hands-On Design Patterns with C++

What is type erasure?

Type erasure, in general, is a programming technique by which the explicit type information is removed from the program. It is a type of abstraction that ensures that the program does not explicitly depend on some of the data types.

This definition, while perfectly correct, also serves perfectly to surround type erasure in mystery. It does so by employing a sort of circular reasoning—it dangles before you the hope for something that, at first glance, appears impossible—a program written in a strongly typed language that does not use the actual types. How can this be? Why, by abstracting away the type, of course! And so, the hope and the mystery lives on.

It is hard to imagine a program that uses types without explicitly ...