Class template apply_visitor_delayed

Class template apply_visitor_delayed_t

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

Synopsis

// In header: <boost/variant/apply_visitor.hpp>

template<typename Visitor> 
class apply_visitor_delayed_t {
public:
  // 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 Variant> result_type operator()(Variant &);
  template<typename Variant1, typename Variant2> 
    result_type operator()(Variant1 &, Variant2 &);
};

Description

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.

See apply_visitor_delayed_cpp14_t which is used on C++14 compatible compilers when Visitor has no result_type typedef.

`apply_visitor_delayed_t` public construct/copy/destruct

```
explicit apply_visitor_delayed_t(Visitor & visitor);
```
Effects:
Constructs the function object with the given visitor.

`apply_visitor_delayed_t` function object interface

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

Function call operator.

Invokes apply_visitor on the stored visitor using the given operands.

Notes:

Version with variadic templates is used by default if BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES is not defined.