gul14/variant.h

Detailed Description

Backport of std::variant from C++17.

Classes
class	gul14::bad_variant_access
	The exception thrown if the wrong type is accessed on a gul14::variant. More...
class	gul14::variant< Ts >
	A "type-safe union". More...
struct	gul14::OverloadSet< Fct1, Fcts >
	A function object that works like an overload set of functions. More...
struct	gul14::OverloadSet< Fct1 >
	OverloadSet for a single function object. More...

Functions
virtual const char *	gul14::bad_variant_access::what () const noexcept override
template<typename Visitor , typename... Variants>
constexpr decltype(auto)	gul14::visit (Visitor &&visitor_fct, Variants &&... variants)
	Call a visitor function with the actual objects stored in the given variants. More...
	gul14::OverloadSet< Fct1, Fcts >::OverloadSet (Fct1 f1, Fcts... fs)
	gul14::OverloadSet< Fct1 >::OverloadSet (Fct1 f1)
template<typename... Fct>
auto	gul14::make_overload_set (Fct... f)
	Create an OverloadSet from an arbitrary number of function objects. More...

Function Documentation

make_overload_set()

template<typename... Fct>

auto gul14::make_overload_set

(

Fct...

f

)

Create an OverloadSet from an arbitrary number of function objects.

This function creates an OverloadSet from the function objects given to it. This is particularly helpful for using multiple lambdas with visit():

gul14::variant<int, double> v = 1.0;
gul14::visit(gul14::make_overload_set(
    [](int) { std::cout << "int\n"; },
    [](double) { std::cout << "double\n"; }
), v);

Since

GUL version 2.9.2

visit()

template<typename Visitor , typename... Variants>

constexpr decltype(auto) gul14::visit ( Visitor &&  visitor_fct, Variants &&...  variants  )

inlineconstexpr

Call a visitor function with the actual objects stored in the given variants.

This function works like std::visit from the C++17 standard library. It is often convenient to use it with make_overload_set():

gul14::variant<int, double> v = 1.0;
gul14::visit(gul14::make_overload_set(
    [](int) { std::cout << "int\n"; },
    [](double) { std::cout << "double\n"; }
), v);

Since

GUL version 2.9.0