E. Gladyshev wrote: >> Are you aware that the pImpl idiom is used for many >> different things > > It defenitly has its place but not in modern C++. > >> or have >> you just decided its not modern C++ at all because >> you don't use it for the >> things you want to do ? > > In my opinion modern C++ is more oriented toward > program specifications and generic (compile-time) > programming. In modern C++, the program functionality > can be customized by specifying custom data types and > using them in a generic way (library). It is more > like a type oriented programming not implementation > driven. pImpl doesn't fit there.
The pImpl technique is an idiom for hiding the private methods and data members of a class from the view of the user of that class. It has aesthetic appeal for me. It makes the user of the class see only what is relevant in the class, while putting the implementation details of the class interface somewhere else. That it also speeds up compilation by not having the class, as the compiler sees it, change when the internal class as represented by its private pImpl pointer changes, is a side benefit to it but not one I consider overridingly important. I agree that it achieves little other than an aesthetic view of class internals and a speed up in build times when a class's implementation, as opposed to its end-user interface, changes. As such there is no pragmatic design reason why it is necessary. These are the major reasons, as I understand it, why the pImpl idiom is generally used and why I have used it. But there may be other reasons. I don't understand what this has to do with modern C++ as you see it. But I think that your view of modern C++, a term perhaps taken from Mr. Alexandrescu's fine book on template programming and metaprogramming techniques, and nurtured by some of the equally fine work done by Boost implementors, may be severely limited. I only hope that you don't get into the habit of seeing all of modern C++ programming as template programming only, and view all other programming and design idioms from that perspective. To me this ioos what you are doing by syaing that the pImpl is not part of modern C++. _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
