whole_func_string: function arrayToRoseTrees(array, fun) {
    return array.map(function(element) {
      return new RoseTree(element, function() { return fun(element); });
    });
  }
func_code_string: function arrayToRoseTrees(array, fun) {
    return array.map(function(element) {
      return new RoseTree(element, function() { return fun(element); });
    });
  }
func_documentation_string: Given array and fun, returns an array of rose trees where each tree's root is the element and its children are fun(element). [a] -> (a -> [a]) -> RoseTree a