Use std::any for type safety
Introduced with C++17, the std::any class provides a type-safe container for a single object of any type.
For example, this is a default-constructed any object:
any x{};
This object has no value. We can test that with the has_value() method:
if(x.has_value()) cout << "have value\n"; else cout << "no value\n";
Output:
no value
We assign a value to the any object with the assignment operator:
x = 42;
Now, the any object has a value, and a type:
if(x.has_value()) {
cout << format("x has type: {}\n", x.type().name());
cout << format("x has value: {}\n", any_cast<int>(x));
} else {
cout << "no value\n";
}
Output:
x has type: i x has value: 42
The type() method returns a type_info object. The type_info::name() method returns an implementation-defined name for the type...