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|
-- 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 getmetatable = getmetatable;
local t_concat = table.concat;
local _ENV = nil;
-- luacheck: std none
local set_mt = { __name = "set" };
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
function set_mt:__freeze()
local a, i = {}, 1;
for item in self._items do
a[i], i = item, i+1;
end
return a;
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 set:add(item)
items[item] = true;
end
function set:contains(item)
return items[item];
end
function set:items()
return next, items;
end
function set:remove(item)
items[item] = nil;
end
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 otherset do
items[item] = true;
end
end
function set:exclude(otherset)
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 setmetatable(set, set_mt);
end
local function union(set1, set2)
local set = new();
local items = set._items;
for item in pairs(set1._items) do
items[item] = true;
end
for item in pairs(set2._items) do
items[item] = true;
end
return set;
end
local function difference(set1, set2)
local set = new();
local items = set._items;
for item in pairs(set1._items) do
items[item] = (not set2._items[item]) or nil;
end
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
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)
if getmetatable(set1) ~= set_mt or getmetatable(set2) ~= set_mt then
-- Lua 5.3+ calls this if both operands are tables, even if metatables differ
return false;
end
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;
};
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