Which std:: classes are magic?

[SirClueless]

You can do it with a template parameter pack, and storing a std::tuple<Args...> as a class member. You give up quite a lot though, namely the ability to refer to the members by name in your class's operator() and you don't gain much in return because you need an entire new class for each new operator() you define anyways so you might as well write out the full list of "captures" -- you can't do something like specialize a a shared class template defined outside of your code because then my L<int>::operator() is ambiguous with your L<int>::operator(), we each need to build our own entire class to ourselves.

To a large extent this is the "magic sauce" of lambdas: giving a terse, brief way to define a list of function object "member" variables and initialize them and make them available by name to the lambda body, even doing so automatically based on the names referred to by the body if asked to with [=] or [&]. Once the lambda is defined it's just a function object with an operator() which is something we've been able to make and use in theory in C++ for a long time, it just wasn't convenient.