text: // CodeMirror, copyright (c) by Marijn Haverbeke and others
  // Distributed under an MIT license: http://codemirror.net/LICENSE
  
  (function (mod) {
      if (typeof exports == "object" && typeof module == "object") // CommonJS
          mod(require("../.."));
      else if (typeof define == "function" && define.amd) // AMD
          define(["../.."], mod);
      else // Plain browser env
          mod(CodeMirror);
  })(function (CodeMirror) {
      "use strict";
  
      CodeMirror.registerHelper("fold", "markdown", function (cm, start) {
          var maxDepth = 100;
  
          function isHeader(lineNo) {
              var tokentype = cm.getTokenTypeAt(CodeMirror.Pos(lineNo, 0));
              return tokentype && /\bheader\b/.test(tokentype);
          }
  
          function headerLevel(lineNo, line, nextLine) {
              var match = line && line.match(/^#+/);
              if (match && isHeader(lineNo)) return match[0].length;
              match = nextLine && nextLine.match(/^[=\-]+\s*$/);
              if (match && isHeader(lineNo + 1)) return nextLine[0] == "=" ? 1 : 2;
              return maxDepth;
          }
  
          var firstLine = cm.getLine(start.line), nextLine = cm.getLine(start.line + 1);
          var level = headerLevel(start.line, firstLine, nextLine);
          if (level === maxDepth) return undefined;
  
          var lastLineNo = cm.lastLine();
          var end = start.line, nextNextLine = cm.getLine(end + 2);
          while (end < lastLineNo) {
              if (headerLevel(end + 1, nextLine, nextNextLine) <= level) break;
              ++end;
              nextLine = nextNextLine;
              nextNextLine = cm.getLine(end + 2);
          }
  
          return {
              from: CodeMirror.Pos(start.line, firstLine.length),
              to: CodeMirror.Pos(end, cm.getLine(end).length)
          };
      });
  
  });
  