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-rw-r--r--util/set.lua10
1 files changed, 8 insertions, 2 deletions
diff --git a/util/set.lua b/util/set.lua
index 02fabc6a..b7345e7e 100644
--- a/util/set.lua
+++ b/util/set.lua
@@ -6,8 +6,8 @@
-- COPYING file in the source package for more information.
--
-local ipairs, pairs, setmetatable, next, tostring =
- ipairs, pairs, setmetatable, next, tostring;
+local ipairs, pairs, getmetatable, setmetatable, next, tostring =
+ ipairs, pairs, getmetatable, setmetatable, next, tostring;
local t_concat = table.concat;
local _ENV = nil;
@@ -31,6 +31,11 @@ function set_mt:__freeze()
return a;
end
+local function is_set(o)
+ local mt = getmetatable(o);
+ return mt == set_mt;
+end
+
local function new(list)
local items = setmetatable({}, items_mt);
local set = { _items = items };
@@ -171,6 +176,7 @@ end
return {
new = new;
+ is_set = is_set;
union = union;
difference = difference;
intersection = intersection;