Modern C++ Design: Generic Programming and Design Patterns Applied

5. Generalized Functors

This chapter describes generalized functors, a powerful abstraction that allows decoupled interobject communication. Generalized functors are especially useful in designs that need requests to be stored in objects. The design pattern that describes encapsulated requests, and that generalized functors follow, is Command (Gamma et al. 1995).

In brief, a generalized functor is any processing invocation that C++ allows, encapsulated as a typesafe first-class object. In a more detailed definition, a generalized functor

• Encapsulates any processing invocation because it accepts pointers to simple functions, pointers to member functions, functors, and even other generalized functors—together with some or all of their respective ...