28 	local a, i = {}, 1;

    28 	local a, i = {}, 1;

    29 	for item in self._items do

    29 	for item in self._items do

    30 		a[i], i = item, i+1;

    30 		a[i], i = item, i+1;

    31 	end

    31 	end

    32 	return a;

    32 	return a;

    33 end

    38 end

    34 

    39 

    35 local function new(list)

    40 local function new(list)

    36 	local items = setmetatable({}, items_mt);

    41 	local items = setmetatable({}, items_mt);

    37 	local set = { _items = items };

    42 	local set = { _items = items };

   175 	return t_concat(s, ", ");

   180 	return t_concat(s, ", ");

   176 end

   181 end

   177 

   182 

   178 return {

   183 return {

   179 	new = new;

   184 	new = new;

   180 	union = union;

   186 	union = union;

   181 	difference = difference;

   187 	difference = difference;

   182 	intersection = intersection;

   188 	intersection = intersection;

   183 	xor = xor;

   189 	xor = xor;

   184 };

   190 };