public XmlTree scan ()
		throws XmlReaderException
	{	while (true)
		{	while (true)
			{	int c=read();
				if (c==-1) return null;
				if (c=='<') break;
			}
			if (found("?xml"))
			{	String s=scanFor("?>");
				if (s==null) return null;
				XmlTree t=new XmlTree(new XmlTagRoot());
				t.addchild(new XmlTree(new XmlTagPI(s)));
				scanContent(t);
				return t;
			}
		}
	}