code: function(o, callback, type, visited) {
  			visited = visited || {};
  			for (var i in o) {
  				if (o.hasOwnProperty(i)) {
  					callback.call(o, i, o[i], type || i);
  
  					if (_.util.type(o[i]) === 'Object' && !visited[_.util.objId(o[i])]) {
  						visited[_.util.objId(o[i])] = true;
  						_.languages.DFS(o[i], callback, null, visited);
  					}
  					else if (_.util.type(o[i]) === 'Array' && !visited[_.util.objId(o[i])]) {
  						visited[_.util.objId(o[i])] = true;
  						_.languages.DFS(o[i], callback, i, visited);
  					}
  				}
  			}
  		}
docs: Traverse a language definition with Depth First Search