The type must be a model of . The type must be a model of .

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.

The result of applying the CallableTransform.

Applies the transform.