The PImpl idiom and the C++26 std:indirect type

The PImpl (Pointer to Implementation) idiom separates a class's interface from its implementation details by hiding them behind an opaque pointer, reducing compile-time dependencies. The article demonstrates traditional PImpl implementation using raw pointers and the Rule of Five (requiring explicit definitions of destructor, copy/move constructors, and assignment operators), using a Widget UI element example. C++26 introduces `std::indirect`, a new type that simplifies PImpl implementation by handling memory management automatically, eliminating the need for manual special member function definitions.