In DOM (Document Object Model) specification, interface Node has a method:
Node GetChild();
It states that if Node has no child then a return value is NULL. What is the right way to implement this approach in C++ without returning a pointer to a child Node. (Better to prevent from memory leaks)
Suggestion:
Have an attribute
bool is_null_;
and overload operator bool() to return this value.
Node child = node.GetChild();
if (child) { ... }
Waiting a bit now, but the Library Fundamentals TS will be providing std::experimental::optional.
Elsewise if you can use boost::optional, which has similar semantics.
You can use it like:
using std::experimental::optional;
optional<Node> GetChild();
auto child = node.GetChild();
if (child) {
const Node& childNode = child.value();
} else {
std::cerr << "parent had no child" << std::endl;
}
const Node& childNode = *child; is the way the cool kids do it.
const Node& childNode = *child; You have to take make sure not to release child. And passing around this reference in other classes methods might be a problem. I prefer std::shared_pointer<Node>Such thing as boost::optional will help you:
http://www.boost.org/doc/libs/1_56_0/libs/optional/doc/html/index.html
