Call single public function of a class without using its name

Is it possible to invoke the function of a class based on the fact that it is the only public one ? What I mean:

Something like:

double res = MyClass().myFunction(n);

becomes

double res = MyClass()[0](n);

Ideally I would have liked to call the function using a string with its name:

double res = MyClass().reflection("myFunction")(n);

But it seems not possible without wasting at least twice the ink to write the function name (function pointer and corresponding string in a map).