michael@0: CodeMirror.registerGlobalHelper("fold", "comment", function(mode) {
michael@0:   return mode.blockCommentStart && mode.blockCommentEnd;
michael@0: }, function(cm, start) {
michael@0:   var mode = cm.getModeAt(start), startToken = mode.blockCommentStart, endToken = mode.blockCommentEnd;
michael@0:   if (!startToken || !endToken) return;
michael@0:   var line = start.line, lineText = cm.getLine(line);
michael@0: 
michael@0:   var startCh;
michael@0:   for (var at = start.ch, pass = 0;;) {
michael@0:     var found = at <= 0 ? -1 : lineText.lastIndexOf(startToken, at - 1);
michael@0:     if (found == -1) {
michael@0:       if (pass == 1) return;
michael@0:       pass = 1;
michael@0:       at = lineText.length;
michael@0:       continue;
michael@0:     }
michael@0:     if (pass == 1 && found < start.ch) return;
michael@0:     if (/comment/.test(cm.getTokenTypeAt(CodeMirror.Pos(line, found + 1)))) {
michael@0:       startCh = found + startToken.length;
michael@0:       break;
michael@0:     }
michael@0:     at = found - 1;
michael@0:   }
michael@0: 
michael@0:   var depth = 1, lastLine = cm.lastLine(), end, endCh;
michael@0:   outer: for (var i = line; i <= lastLine; ++i) {
michael@0:     var text = cm.getLine(i), pos = i == line ? startCh : 0;
michael@0:     for (;;) {
michael@0:       var nextOpen = text.indexOf(startToken, pos), nextClose = text.indexOf(endToken, pos);
michael@0:       if (nextOpen < 0) nextOpen = text.length;
michael@0:       if (nextClose < 0) nextClose = text.length;
michael@0:       pos = Math.min(nextOpen, nextClose);
michael@0:       if (pos == text.length) break;
michael@0:       if (pos == nextOpen) ++depth;
michael@0:       else if (!--depth) { end = i; endCh = pos; break outer; }
michael@0:       ++pos;
michael@0:     }
michael@0:   }
michael@0:   if (end == null || line == end && endCh == startCh) return;
michael@0:   return {from: CodeMirror.Pos(line, startCh),
michael@0:           to: CodeMirror.Pos(end, endCh)};
michael@0: });