-local ipairs, pairs =
- ipairs, pairs;
+-- 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.
+--
-module "set"
+local ipairs, pairs, setmetatable, next, tostring =
+ ipairs, pairs, setmetatable, next, tostring;
+local t_concat = table.concat;
+
+local _ENV = nil;
+
+local set_mt = {};
+function set_mt.__call(set, _, k)
+ return next(set._items, k);
+end
+
+local items_mt = {};
+function items_mt.__call(items, _, k)
+ return next(items, k);
+end
+
+local function new(list)
+ local items = setmetatable({}, items_mt);
+ local set = { _items = items };
+
+ -- We access the set through an upvalue in these methods, so ignore 'self' being unused
+ --luacheck: ignore 212/self
-function new(list)
- local items = {};
- local set = { items = items };
-
function set:add(item)
items[item] = true;
end
-
+
function set:contains(item)
return items[item];
end
-
+
function set:items()
- return items;
+ return next, items;
end
-
+
function set:remove(item)
items[item] = nil;
end
-
- function set:add_list(list)
- for _, item in ipairs(list) do
- items[item] = true;
+
+ function set:add_list(item_list)
+ if item_list then
+ for _, item in ipairs(item_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;
+
+ return setmetatable(set, set_mt);
end
-function union(set1, set2)
+local function union(set1, set2)
local set = new();
- local items = set.items;
-
- for item in pairs(set1.items) do
+ local items = set._items;
+
+ for item in pairs(set1._items) do
items[item] = true;
end
- for item in pairs(set2.items) do
+ for item in pairs(set2._items) do
items[item] = true;
end
-
+
return set;
end
-function difference(set1, set2)
+local function difference(set1, set2)
local set = new();
- local items = set.items;
-
- for item in pairs(set1.items) do
- items[item] = true;
+ local items = set._items;
+
+ for item in pairs(set1._items) do
+ items[item] = (not set2._items[item]) or nil;
end
- for item in pairs(set2.items) do
- items[item] = nil;
+ return set;
+end
+
+local function intersection(set1, set2)
+ local set = new();
+ local items = set._items;
+
+ set1, set2 = set1._items, set2._items;
+
+ for item in pairs(set1) do
+ items[item] = (not not set2[item]) or nil;
end
-
+
return set;
end
-return _M;
+local function xor(set1, set2)
+ return union(set1, set2) - intersection(set1, set2);
+end
+
+function set_mt.__add(set1, set2)
+ return union(set1, set2);
+end
+function set_mt.__sub(set1, set2)
+ return difference(set1, set2);
+end
+function set_mt.__div(set, func)
+ local new_set = new();
+ local items, new_items = set._items, new_set._items;
+ for item in pairs(items) do
+ local new_item = func(item);
+ if new_item ~= nil then
+ new_items[new_item] = true;
+ end
+ end
+ return new_set;
+end
+function set_mt.__eq(set1, set2)
+ set1, set2 = set1._items, set2._items;
+ for item in pairs(set1) do
+ if not set2[item] then
+ return false;
+ end
+ end
+
+ for item in pairs(set2) do
+ if not set1[item] then
+ return false;
+ end
+ end
+
+ return true;
+end
+function set_mt.__tostring(set)
+ local s, items = { }, set._items;
+ for item in pairs(items) do
+ s[#s+1] = tostring(item);
+ end
+ return t_concat(s, ", ");
+end
+
+return {
+ new = new;
+ union = union;
+ difference = difference;
+ intersection = intersection;
+ xor = xor;
+};