     xmlTagStart.lastIndex = iter.ch;
      var found = xmlTagStart.exec(iter.text);
      if (!found) { if (nextLine(iter)) continue; else return; }
      if (!tagAt(iter, found.index + 1)) { iter.ch = found.index + 1; continue; }
      iter.ch = found.index + found[0].length;
      return found;
    }
  }
  function toPrevTag(iter) {
    for (;;) {
      var gt = iter.ch ? iter.text.lastIndexOf(">", iter.ch - 1) : -1;
      if (gt == -1) { if (prevLine(iter)) continue; else return; }
      if (!tagAt(iter, gt + 1)) { iter.ch = gt; continue; }
      var lastSlash = iter.text.lastIndexOf("/", gt);
      var selfClose = lastSlash > -1 && !/\S/.test(iter.text.slice(lastSlash + 1, gt));
      iter.ch = gt + 1;
      return selfClose ? "selfClose" : "regular";
    }
  }

  function findMatchingClose(iter, tag) {
    var stack = [];
    for (;;) {
      var next = toNextTag(iter), end, startLine = iter.line, startCh = iter.ch - (next ? next[0].length : 0);
      if (!next || !(end = toTagEnd(iter))) return;
      if (end == "selfClose") continue;
      if (next[1]) { // closing tag
        for (var i = stack.length - 1; i >= 0; --i) if (stack[i] == next[2]) {
          stack.length = i;
          break;
        }
        if (i < 0 && (!tag || tag == next[2])) return {
          tag: next[2],
          from: Pos(startLine, startCh),
          to: Pos(iter.line, iter.ch)
        };
      } else { // opening tag
        stack.push(next[2]);
      }
    }
  }
  function findMatchingOpen(iter, tag) {
    var stack = [];
    for (;;) {
      var prev = toPrevTag(iter);
      if (!prev) return;
      if (prev == "selfClose") { toTagStart(iter); continue; }
      var endLine = iter.line, endCh = iter.ch;
      var start = toTagStart(iter);
      if (!start) return;
      if (start[1]) { // closing tag
        stack.push(start[2]);
      } else { // opening tag
        for (var i = stack.length - 1; i >= 0; --i) if (stack[i] == start[2]) {
          stack.length = i;
          break;
        }
        if (i < 0 && (!tag || tag == start[2])) return {
          tag: start[2],
          from: Pos(iter.line, iter.ch),
          to: Pos(endLine, endCh)
        };
      }
    }
  }

  CodeMirror.registerHelper("fold", "xml", function(cm, start) {
    var iter = new Iter(cm, start.line, 0);
    for (;;) {
      var openTag = toNextTag(iter)
      if (!openTag || iter.line != start.line) return
      var end = toTagEnd(iter)
      if (!end) return
      if (!openTag[1] && end != "selfClose") {
        var startPos = Pos(iter.line, iter.ch);
        var endPos = findMatchingClose(iter, openTag[2]);
        return endPos && cmp(endPos.from, startPos) > 0 ? {from: startPos, to: endPos.from} : null
      }
    }
  });
  CodeMirror.findMatchingTag = function(cm, pos, range) {
    var iter = new Iter(cm, pos.line, pos.ch, range);
    if (iter.text.indexOf(">") == -1 && iter.text.indexOf(