Added an iterator class that can iterate through both sequence and map nodes.

iterator.cpp

@@ -0,0 +1,73 @@
+#include "node.h"
+#include "exceptions.h"
+
+namespace YAML
+{
+	Node::Iterator::Iterator(): type(IT_NONE)
+	{
+	}
+
+	Node::Iterator::Iterator(std::vector <Node *>::const_iterator it): seqIter(it), type(IT_SEQ)
+	{
+	}
+
+	Node::Iterator::Iterator(std::map <Node *, Node *>::const_iterator it): mapIter(it), type(IT_MAP)
+	{
+	}
+
+	Node::Iterator::~Iterator()
+	{
+	}
+
+	Node::Iterator& Node::Iterator::operator ++ ()
+	{
+		if(type == IT_SEQ)
+			++seqIter;
+		else if(type == IT_MAP)
+			++mapIter;
+
+		return *this;
+	}
+
+	const Node& Node::Iterator::operator * ()
+	{
+		if(type == IT_SEQ)
+			return **seqIter;
+
+		throw BadDereference();
+	}
+
+	const Node& Node::Iterator::first()
+	{
+		if(type == IT_MAP)
+			return *mapIter->first;
+
+		throw BadDereference();
+	}
+
+	const Node& Node::Iterator::second()
+	{
+		if(type == IT_MAP)
+			return *mapIter->second;
+
+		throw BadDereference();
+	}
+
+	bool operator == (const Node::Iterator& it, const Node::Iterator& jt)
+	{
+		if(it.type != jt.type)
+			return false;
+
+		if(it.type == Node::Iterator::IT_SEQ)
+			return it.seqIter == jt.seqIter;
+		else if(it.type == Node::Iterator::IT_MAP)
+			return it.mapIter == jt.mapIter;
+
+		return true;
+	}
+
+	bool operator != (const Node::Iterator& it, const Node::Iterator& jt)
+	{
+		return !(it == jt);
+	}
+}