...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
CallableTransform
A CallableTransform is a function type or a function pointer type where the return type Fn is a PolymorphicFunctionObject and the arguments are Transforms. is_callable< Fn >::value must be true. The CallableTransform, when applied, has the effect of invoking the polymorphic function object Fn, passing as arguments the result(s) of applying transform(s) Tn.
result_type
boost::result_of<Fn(Transform<Tn, Expr, State, Data>::result_type...)>::type
The result of applying the CallableTransform.
fn
expr
state
data