Organization

The book consists of two major parts: techniques and components. Part I (Chapters 1 to 4) describes the C++ techniques that are used in generic programming and in particular in building generic components. A host of C++-specific features and techniques are presented: policy-based design, partial template specialization, typelists, local classes, and more. You may want to read this part sequentially and return to specific sections for reference.

Part II builds on the foundation established in Part I by implementing a number of generic components. These are not toy examples; they are industrial-strength components used in real-world applications. Recurring issues that C++ developers face in their day-to-day activity, such as smart pointers, object factories, and functor objects, are discussed in depth and implemented in a generic way. The text presents implementations that address basic needs and solve fundamental problems. Instead of explaining what a body of code does, the approach of the book is to discuss problems, take design decisions, and implement those decisions gradually.

Chapter 1 presents policies—a C++ idiom that helps in creating flexible designs.

Chapter 2 discusses general C++ techniques related to generic programming.

Chapter 3 implements typelists, which are powerful type manipulation structures.

Chapter 4 introduces an important ancillary tool: a small-object allocator.

Chapter 5 introduces the concept of generalized functors, useful in designs that use the Command design pattern.

Chapter 6 describes Singleton objects.

Chapter 7 discusses and implements smart pointers.

Chapter 8 describes generic object factories.

Chapter 9 treats the Abstract Factory design pattern and provides implementations of it.

Chapter 10 implements several variations of the Visitor design pattern in a generic manner.

Chapter 11 implements several multimethod engines, solutions that foster various trade-offs.

The design themes cover many important situations that C++ programmers have to cope with on a regular basis. I personally consider object factories (Chapter 8) a cornerstone of virtually any quality polymorphic design. Also, smart pointers (Chapter 7) are an important component of many C++ applications, small and large. Generalized functors (Chapter 5) have an incredibly broad range of applications. Once you have generalized functors, many complicated design problems become very simple. The other, more specialized, generic components, such as Visitor (Chapter 10) or multimethods (Chapter 11), have important niche applications and stretch the boundaries of language support.