My question is how the following line can be parsed as a function declaration:
vector<int> v(istream_iterator<int>(cin), istream_iterator<int>());
I understand most of the details of the Most Vexing Parse and why the second temporary iterator can be interpreted as a type that is a function returning an iterator and taking no arguments, but what I don't get is why the first temporary iterator can be interpreted as a type. What type does it represent? My thought is that it would be some sort of function type, but I can't see how the name cin gets used. Is it declaring that the parameter is an istream_iterator<int> named cin? If so, does that mean that you can arbitrarily parenthesize the names of arguments to functions? And if so, why?