== method should be insensitive to attribute order

[MarkNahabedian]

Given that:

• attribute order is not significant in XML,
• the Node constructors in this package do not preserve attribute order;

the method of Base.==(::Node, ::Node) should compare attributes independent of their order in each element.

This works for me:

function node_equal(a::XML.Node, b::XML.Node)
    function attrs_equal(a1, a2)
        if a1 == nothing && a2 == nothing
            return true
        end
        if a1 == nothing || a2 == nothing
            return false
        end
        for key in union(keys(a1), keys(a2))
            if get(a1, key, nothing) != get(a2, key, nothing)
                return false
            end
        end
        return true
    end
    a.type == b.type &&
        a.tag == b.tag &&
        attrs_equal(a.attributes, b.attributes) &&
        a.children == b.children
end

[joshday]

For XML.Node, this is already handled by the == method for Dicts.

However, XML.Element uses an OrderedDict (for which order matters in checking equality) and the == method needs to be adjusted.

[joshday]

Actually I take that back. Looks like neither Dict nor OrderedDict depend on order for equality.

[MarkNahabedian]

Sorry for the false alarm.

I wonder what else was going on that I accidentally fixed in my own project that I thought node_equal had fixed.