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Adaptable Binary Function


Category: functors	Component type: concept

Description

An Adaptable Binary Function is a Binary Function with nested typedefs that define its argument types and result type. [1] [2] These nested typedefs make it possible to use function object adaptors.

Refinement of

Binary Function

Associated types

First argument type	`F::first_argument_type`	The type of `F`'s first argument
Second argument type	`F::second_argument_type`	The type of `F`'s second argument
Result type	`F::result_type`	The type returned when the Binary Function is called

Notation

`F`	A type that is a model of Binary Function

Definitions

Valid expressions

None, except for those defined by Binary Function

Expression semantics

Complexity guarantees

Invariants

Models

Notes

[1] Note the implication of this: a function pointer T (*f)(X,Y) is a Binary Function, but not an Adaptable Binary Function: the expressions f::first_argument_type, f::second_argument_type, and f::result_type are nonsensical.

[2] When you define a class that is a model of Adaptable Binary Function, you must provide these typedefs. The easiest way to do this is to derive the class from the base class binary_function. This is an empty class, with no member functions or member variables; the only reason it exists is to make defining Adaptable Binary Functions more convenient. Binary_function is very similar to the base classes used by the iterator tag functions.