-local ipairs, pairs, setmetatable, next, tostring =
+-- Prosody IM
+-- Copyright (C) 2008-2010 Matthew Wild
+-- Copyright (C) 2008-2010 Waqas Hussain
+--
+-- This project is MIT/X11 licensed. Please see the
+-- COPYING file in the source package for more information.
+--
+
+local ipairs, pairs, setmetatable, next, tostring =
ipairs, pairs, setmetatable, next, tostring;
local t_concat = table.concat;
return _M.difference(set1, set2);
end
function set_mt.__div(set, func)
- local new_set, new_items = _M.new();
+ local new_set = _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
function set:include(otherset)
- for item in pairs(otherset) do
+ for item in otherset do
items[item] = true;
end
end
function set:exclude(otherset)
- for item in pairs(otherset) do
+ for item in otherset do
items[item] = nil;
end
end
+ function set:empty()
+ return not next(items);
+ end
+
if list then
set:add_list(list);
end
return set;
end
+function xor(set1, set2)
+ return union(set1, set2) - intersection(set1, set2);
+end
+
return _M;