private static void ConvertPost(SiteUris uris, XmlReader r, SequentialTurtleWriter w, UnknownValueStore <string> unknownPostTypeIds)
        {
            Uri subjectUri;

            if (r.MoveToAttribute("Id"))
            {
                subjectUri = uris.CreatePostUri(r.Value);
                w.StartTriple(subjectUri);
            }
            else
            {
                r.MoveToElement();
                ConsoleHelper.WriteErrorLine("No Id attribute found on element {0}. Skipping element.", r.ReadOuterXml());
                return;
            }

            if (r.MoveToAttribute("PostTypeId"))
            {
                switch (r.Value)
                {
                case "1":                         // question
                    w.AddToTriple(uris.GeneralUris.TypeProperty, uris.GeneralUris.QuestionType);
                    uris.LinkToSite(w);
                    if (r.MoveToAttribute("AcceptedAnswerId"))
                    {
                        w.AddToTriple(uris.GeneralUris.AcceptedAnswerProperty, uris.CreatePostUri(r.Value));
                    }
                    if (r.MoveToAttribute("ViewCount"))
                    {
                        w.AddToTriple(uris.GeneralUris.ViewCountProperty, long.Parse(r.Value));
                    }
                    if (r.MoveToAttribute("Title"))
                    {
                        w.AddToTriple(uris.GeneralUris.TitleProperty, r.Value);
                        w.AddToTriple(uris.GeneralUris.LabelProperty, r.Value);
                    }
                    if (r.MoveToAttribute("Score"))
                    {
                        w.AddToTriple(uris.GeneralUris.ScoreProperty, long.Parse(r.Value));
                    }
                    break;

                case "2":                         // answer
                    w.AddToTriple(uris.GeneralUris.TypeProperty, uris.GeneralUris.AnswerType);
                    uris.LinkToSite(w);
                    if (r.MoveToAttribute("ParentId"))
                    {
                        w.StartTriple(uris.CreatePostUri(r.Value));
                        w.AddToTriple(uris.GeneralUris.AnswerProperty, subjectUri);
                        w.StartTriple(subjectUri);
                    }
                    else
                    {
                        ConsoleHelper.WriteWarningLine("Orphaned answer: {0}", subjectUri);
                    }
                    if (r.MoveToAttribute("Score"))
                    {
                        w.AddToTriple(uris.GeneralUris.ScoreProperty, long.Parse(r.Value));
                    }
                    break;

                case "3":                         // orphaned tag wiki
                    break;

                case "4":                         // tag info excerpt
                    w.AddToTriple(uris.GeneralUris.TypeProperty, uris.GeneralUris.TagExcerptType);
                    break;

                case "5":                         // tag description
                    w.AddToTriple(uris.GeneralUris.TypeProperty, uris.GeneralUris.TagDescriptionType);
                    break;

                case "6":                         // moderator nomination
                    break;

                case "7":                         // "Wiki placeholder" (seems to only be the election description)
                    //w.AddToTriple(uris.GeneralUris.TypeProperty, uris.GeneralUris.SiteInfoType);
                    break;

                default:
                    unknownPostTypeIds.RegisterUnknownValue(r.Value);
                    break;
                }
                if (r.MoveToAttribute("CreationDate"))
                {
                    w.AddToTriple(uris.GeneralUris.DateProperty, DateTime.Parse(r.Value, System.Globalization.CultureInfo.InvariantCulture));
                }
                if (r.MoveToAttribute("LastEditDate"))
                {
                    w.AddToTriple(uris.GeneralUris.LastEditDateProperty, DateTime.Parse(r.Value, System.Globalization.CultureInfo.InvariantCulture));
                }
                if (r.MoveToAttribute("LastActivity"))
                {
                    w.AddToTriple(uris.GeneralUris.LastActivityDateProperty, DateTime.Parse(r.Value, System.Globalization.CultureInfo.InvariantCulture));
                }
                if (r.MoveToAttribute("OwnerUserId"))
                {
                    w.AddToTriple(uris.GeneralUris.OwnerProperty, uris.CreateUserUri(r.Value));
                }
                // TODO: LastEditorUserId (given in post history)
                // TODO: FavoriteCount (linked to users?)
                if (r.MoveToAttribute("Body"))
                {
                    w.AddToTriple(uris.GeneralUris.DescriptionProperty, r.Value);
                }
                if (r.MoveToAttribute("Tags"))
                {
                    w.AddToTriple(uris.GeneralUris.TagProperty,
                                  tagRegex.Matches(r.Value).Cast <Match>().Select(m => uris.CreateTagUri(m.Groups[1].Value)));
                }
            }
            else
            {
                r.MoveToElement();
                ConsoleHelper.WriteErrorLine("No PostTypeId attribute found on element {0}. Skipping element.", r.ReadOuterXml());
            }
        }