From 4ded26be2c2ffb17ec99efe6356103705466e5ab Mon Sep 17 00:00:00 2001
From: Lars Mueller <appgurulars@gmx.de>
Date: Fri, 30 Sep 2022 12:55:44 +0200
Subject: [PATCH] table.copy: Preserve metatables by default

---
 table.lua | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/table.lua b/table.lua
index 56c8926..549aba9 100644
--- a/table.lua
+++ b/table.lua
@@ -1,6 +1,6 @@
 -- Localize globals
-local assert, ipairs, math, next, pairs, rawget, rawset, setmetatable, select, string, table, type
-	= assert, ipairs, math, next, pairs, rawget, rawset, setmetatable, select, string, table, type
+local assert, ipairs, math, next, pairs, rawget, rawset, getmetatable, setmetatable, select, string, table, type
+	= assert, ipairs, math, next, pairs, rawget, rawset, getmetatable, setmetatable, select, string, table, type
 
 -- Set environment
 local _ENV = {}
@@ -300,16 +300,20 @@ function shallowcopy(table)
 	return copy
 end
 
-function deepcopy_noncircular(table)
+function deepcopy_tree(table)
 	if type(table) ~= "table" then return table end
 	local copy = {}
 	for key, value in pairs(table) do
-		copy[deepcopy_noncircular(key)] = deepcopy_noncircular(value)
+		copy[deepcopy_tree(key)] = deepcopy_tree(value)
 	end
 	return copy
 end
+deepcopy_noncircular = deepcopy_tree
 
-function deepcopy(table)
+function deepcopy(
+	table -- table to copy; reference equality will be preserved
+	, strip_metatables -- whether to strip metatables; falsy by default; metatables are not copied
+)
 	local copies = {}
 	local function _deepcopy(table)
 		local copy = copies[table]
@@ -317,6 +321,9 @@ function deepcopy(table)
 			return copy
 		end
 		copy = {}
+		if not strip_metatables then
+			setmetatable(copy, getmetatable(table))
+		end
 		copies[table] = copy
 		local function _copy(value)
 			if type(value) == "table" then