From f86a45d60a4bc659aabedeae7bc9f698baf6d428 Mon Sep 17 00:00:00 2001
From: Petr Mikheev <ptmikheev@gmail.com>
Date: Sun, 16 Jul 2023 06:17:04 +0200
Subject: [PATCH] [Lua] add __len metafunction for readonly objects

---
 components/lua/luastate.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/components/lua/luastate.cpp b/components/lua/luastate.cpp
index 2a5769e6dd..2269a40c26 100644
--- a/components/lua/luastate.cpp
+++ b/components/lua/luastate.cpp
@@ -246,6 +246,9 @@ namespace LuaUtil
                 local nextFn, t, firstKey = ipairs(getmetatable(v).t)
                 return function(_, k) return nextFn(t, k) end, v, firstKey
             end
+            function lenForReadOnly(v)
+                return #getmetatable(v).t
+            end
             local function nextForArray(array, index)
                 index = (index or 0) + 1
                 if index <= #array then
@@ -300,6 +303,7 @@ namespace LuaUtil
             meta["__index"] = table;
         meta["__pairs"] = lua["pairsForReadOnly"];
         meta["__ipairs"] = lua["ipairsForReadOnly"];
+        meta["__len"] = lua["lenForReadOnly"];
 
         lua_newuserdata(luaState, 0);
         sol::stack::push(luaState, meta);