struct tree
{
	whatever payload;
	std::list<tree*> vertices;
	void * optional_whatever;
}	

operator<<(stream& out, tree& benis)
{
	out<<benis.payload;
	bool nothing= benis.optional_whatever==NULL ;
	out<<nothing;
	if(!nothing)
		out<<*benis.optional_whatever;
	size_t num=benis.vertices.size();
	out<<num;
	for(size_t i=0; i!=num; i++)
		out<<*benis.vertices[i];
}