How can I emulate destructuring in C++?

Question

In JavaScript ES6, there is a language feature known as destructuring. It exists across many other languages as well.

In JavaScript ES6, it looks like this:

var animal = {     species: 'dog',     weight: 23,     sound: 'woof' }  //Destructuring var {species, sound} = animal  //The dog says woof! console.log('The ' + species + ' says ' + sound + '!') 

What can I do in C++ to get a similar syntax and emulate this kind of functionality?

Answer 1

In C++17 this is called structured bindings, which allows for the following:

struct animal {     std::string species;     int weight;     std::string sound; };  int main() {   auto pluto = animal { "dog", 23, "woof" };    auto [ species, weight, sound ] = pluto;    std::cout << "species=" << species << " weight=" << weight << " sound=" << sound << "\n"; } 

Answer 2

For the specific case of std::tuple (or std::pair) objects, C++ offers the std::tie function which looks similar:

std::tuple<int, bool, double> my_obj {1, false, 2.0}; // later on... int x; bool y; double z; std::tie(x, y, z) = my_obj; // or, if we don't want all the contents: std::tie(std::ignore, y, std::ignore) = my_obj; 

I am not aware of an approach to the notation exactly as you present it.