Pass variable to PUGIXML xml_tree_walker - c++

Question

I am using pugixml to parse a file. I have been using an xml_tree_walker and I have a variable I want to modify as the walker walks through the xml. I am currently using a global variable but don't want to. Is there a way to pass a variable to the walker by reference? If this is the case, would that mean I would need to modify the for_each function prototype in the pugixml source?
Below is the way I am currently using the walker.
struct simple_walker: pugi::xml_tree_walker
{
virtual bool for_each(pugi::xml_node& node)
{
for (int i = 0; i < depth(); ++i) std::cout << " "; // indentation
std::cout << node_types[node.type()] << ": name='" << node.name() << "', value='" << node.value() << "'\n";
some_global = node.name(); // I don't want this to be a global
return true; // continue traversal
}
};
I am calling the walker like so:
pugi::xml_document doc;
pugi::xml_parse_result result = doc.load_file(XML_FILE);
simple_walker mySimpleWalker;
doc.traverse(mySimpleWalker);

Answer 1

One thing you can do is keep a member reference in your walker to the object you are capturing information in. Something like:
struct captured_info // where my captured info goes
{
std::string name;
int value;
std::time_t date;
// ...
};
struct simple_walker: pugi::xml_tree_walker
{
// must supply a captured_info object to satisfy
// this constructor
simple_walker(captured_info& info): info(info) {}
virtual bool for_each(pugi::xml_node& node)
{
for (int i = 0; i < depth(); ++i) std::cout << " "; // indentation
std::cout << node_types[node.type()] << ": name='" << node.name() << "', value='" << node.value() << "'\n";
info.name = node.name();
info.value = std::stoi(node.value());
// ... etc
return true; // continue traversal
}
captured_info& info;
};
pugi::xml_document doc;
pugi::xml_parse_result result = doc.load_file(XML_FILE);
captured_info info; // the output!!!
simple_walker mySimpleWalker(info); // configure for output
doc.traverse(mySimpleWalker);
std::cout << info.name << '\n'; // etc...