class: add is(obj, cls)

1 files changed, 12 insertions, 1 deletions

diff --git a/class.lua b/class.lua
index 22cf217..fda1e24 100644
--- a/class.lua
+++ b/class.lua
@@ -23,9 +23,20 @@ local function extend(Base)
 	return T
 end
 
+local function is(obj, cls)
+	if not type(obj) == 'table' then return false end
+	local mt = getmetatable(obj).__index
+	while mt do
+		if rawequal(cls, mt) then return true end
+		mt = (getmetatable(mt) or {}).__index
+	end
+	return false
+end
+
 return setmetatable({
 	class=class,
-	extend=extend
+	extend=extend,
+	is=is,
 },{__call=class})