make_overloaded_function: A single-file header-only library that lets you easily combine lambdas for C++11 and later

A single-file header-only library that lets you easily combine lambdas for use with std::visit and polyfills. The documentation for std::visit gives an example type and function overloaded, but it has issues prior to C++17. This library works all the way back to C++11 (when lambdas were introduced), making it a great fit for std::variant polyfill libraries like variant-lite.

Example usage

#include <make_overloaded_function.hpp>
#include <nonstd/variant.hpp>
#include <vector>

// the variant to visit
using var_t = nonstd::variant<int, long, double, std::string>;

std::vector<var_t> vec = {var_t(10), var_t(15l), var_t(1.5), var_t("hello")};

for (auto& v: vec) {
    nonstd::visit(make_overloaded_function(
        [&](int arg) { out << arg << ' '; },
        [&](long arg) { out << arg << "l "; },
        [&](double arg) { out << std::fixed << arg << ' '; },
        [&](const std::string& arg) { out << arg << ' '; }
    ), v);
}

Output:

10 15l 1.500000 hello

License

make_overloaded_function is distributed under the Boost Software License.

Dependencies

make_overloaded_function has no dependencies other than a C++11-compliant compiler.

variant-lite is recommended as a variant implementation for C++11 and C++14.

API

template <typename ...Fs>
overloaded<Fs...> make_overloaded_function(Fs... args);