Boost C++ Libraries of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

This is an old version of boost. Click here for the latest version's documentation home page.

Class template apply_visitor_delayed_t

boost::apply_visitor_delayed_t — Adapts a visitor for use as a function object.


template<typename Visitor> 
class apply_visitor_delayed_t {
// types
typedef typename Visitor::result_type result_type;

// construct/copy/destruct
explicit apply_visitor_delayed_t(Visitor &);

// function object interface
template<typename Variant> result_type operator()(Variant &);
template<typename Variant1, typename Variant2> 
result_type operator()(Variant1 &, Variant2 &);


Adapts the function given at construction for use as a function object. This is useful, for example, when one needs to operate on each element of a sequence of variant objects using a standard library algorithm such as std::for_each.

See the "visitor-only" form of apply_visitor for a simple way to create apply_visitor_delayed_t objects.

apply_visitor_delayed_t construct/copy/destruct

  1. explicit apply_visitor_delayed_t(Visitor & visitor);

    Effects: Constructs the function object with the given visitor.

apply_visitor_delayed_t function object interface

  1. template<typename Variant> result_type operator()(Variant & operand);
    template<typename Variant1, typename Variant2> 
    result_type operator()(Variant1 & operand1, Variant2 & operand2);

    Invokes apply_visitor on the stored visitor using the given operands.

Copyright 2002, 2003 Eric Friedman, Itay Maman