6 local set = { items = items };
8 function set:add(set, item)
12 function set:contains(set, item)
16 function set:items(set)
20 function set:remove(set, item)
24 function set:add_list(set, list)
25 for _, item in ipairs(list) do
30 function set:include(set, otherset)
31 for item in pairs(otherset) do
36 function set:exclude(set, otherset)
37 for item in pairs(otherset) do
45 function union(set1, set2)
47 local items = set.items;
49 for item in pairs(set1.items) do
53 for item in pairs(set2.items) do
60 function difference(set1, set2)
62 local items = set.items;
64 for item in pairs(set1.items) do
68 for item in pairs(set2.items) do