Question

How can I make something like this work with range based loops for both Elements and Attributes?

#include <list>
#include "XMLAttribute.h"

namespace XML
{
    class Element
    {
        private:
            typedef std::list<Attribute> attribute_container;
            typedef std::list<Element> element_container;

        public:
            XMLElement();

            bool has_attributes() const;
            bool has_elements() const;
            bool has_data() const;

            const std::string &name() const;
            const std::string &data() const;

        private:
            std::string _name;
            std::string _data;

            attribute_container _attributes;
            element_container _elements;
    };
}

I would like to be able to use something like:

for (XML::Element &el : element) { .. }
for (XML::Attribute &at : element) { .. }

And block something like for (auto &some_name : element) { .. } //XML::Element or XML::Attribute?.

Is it a good idea to implement it like this or should I change my design?

Answer 1

The correct answer is to give Element nodes functions that return ranges of child attributes and elements. Thus, you can do this:

for(auto &element : element.child_elements()) {...}
for(auto &attribute : element.attributes()) {...}

Your child_elements function would return some kind of type that stores two iterators, like a boost::iterator_range. attributes would likewise return a range for attribute elements.