local new_set, new_items = _M.new();
local items, new_items = set._items, new_set._items;
for item in pairs(items) do
- if func(item) then
- new_items[item] = true;
+ local new_item = func(item);
+ if new_item ~= nil then
+ new_items[new_item] = true;
end
end
return new_set;
end
function set:add_list(list)
- for _, item in ipairs(list) do
- items[item] = true;
+ if list then
+ for _, item in ipairs(list) do
+ items[item] = true;
+ end
end
end