function (tree) {
                    // http://programmers.stackexchange.com/questions/214227/
                    var stack = [],
                        replies = tree.replies.slice(1, tree.replies.length),
                        root = tree.replies[0];
                    root.children = [];
                    stack.push(root);
                    replies.forEach(function (reply) {
                        var delta = reply.depth - stack.length;
                        reply.children = [];
                        if (delta > 0) {
                            assert(delta === 1);
                            stack.push(stack.front().children.front());
                        }
                        while (delta < 0) {
                            stack.pop();
                            delta++;
                        }
                        stack.front().children.push(reply);
                    });
                    this.rootReply = root;
                },