In Delphi, closures are implemented pretty much exactly as your second variant. They're implemented using a compiler-generated class.
A difference is that you can't specify capture type, all captured variables are stored as fields in the class, and any outer references (such as x here) are replaced to use the field in the instance:
struct GetxFunctionObject {
int x;
int operator()() { return x; }
};
const auto getx = GetxFunctionObject();
getx.x = 5; // compiler automatically changes "x = 5" to this
getx(); // 5
Modulo any it's-too-early-in-the-morning-to-write-C++ mistakes I made.
I can't recall the details if multiple closures captures the same variable, might be the "obvious" solution of a shared data-class instance.
A difference is that you can't specify capture type, all captured variables are stored as fields in the class, and any outer references (such as x here) are replaced to use the field in the instance:
Modulo any it's-too-early-in-the-morning-to-write-C++ mistakes I made.I can't recall the details if multiple closures captures the same variable, might be the "obvious" solution of a shared data-class instance.