PM>Boost.Phoenix is the most important Boost library for functional programming. While libraries like Boost.Bind or Boost.Lambda provide some support for functional programming, Boost.Phoenix includes the features of these libraries and goes beyond them.PM>

In functional programming, functions are objects and can be processed like objects. With Boost.Phoenix, it is possible for a function to return another function as a result. It is also possible to pass a function as a parameter to another function. Because functions are objects, it’s possible to distinguish between instantiation and execution. Accessing a function isn’t equal to executing it.