Part III: Function Objects and Higher-Order Programming - Beyond the C++ Standard Library: An Introduction to Boost [Electronic resources] نسخه متنی

Part III: Function Objects and Higher-Order Programming

The following four libraries have the potential of changing the way you look at programming in C++ forever. Although function objects are not a novel concept, especially for people who have long been using and customizing the algorithms in the Standard Library, the libraries covered in this part of the book take function objects to a whole new level of abstraction. There are areas in C++ that are sometimes considered to be shortcomings when employing certain designs, such as the seemingly unavoidable proliferation of small function objects when using Standard Library algorithms. One must never forget that in C++, it's best to not be (too) judgmental of the language itself, for it was designed to handle its own shortcomings through libraries; and that's exactly what the libraries Boost.Bind and Boost.Lambda try to do for the aforementioned problem. Callback functions are another problematic area that is addressed here; the root of the problem is accentuated by using libraries for higher-order programming, because storing and invoking delayed function-like objects becomes an important feature. That's what Boost.Function does, and of course, it plays very nicely with the other two libraries mentioned here (and others, too). The final chapter discusses Boost.Signals, a library that reifies the Observer pattern. There is fantastic power in these librariesenabling programmers to write less code, more expressive statements, and really compact expressions that make code easier to read and maintain. With this power comes responsibility, because it's also quite possible to write virtually unparseable expressions. For many programmers, the acquaintance with these libraries has been an epiphanyI hope that it will be for you too.