Linking LPeg

[Александр Машин <alex.mashin@...>]

Good time of day,

I am trying to  link LPeg library to a very restrictive Lua environment 
(which is luasandbox Lua engine for PHP written in C++, 
https://github.com/wikimedia/mediawiki-php-luasandbox), which, in 
particular, reloads require () function.

I managed to achieve this, more or less, by running this C++ code:

extern "C" int luaopen_lpeg(lua_State*);
...
lua_pushcfunction(L, luaopen_lpeg);
lua_call(L, 0, 0);

After that, I get lpeg table in my global namespace and can call 
lpeg.P(1), for example.

Unfortunately, getmetatable (lpeg.P(1)) == nil, which makes the library 
useless. The metatable seems to be lost or have benn overwritten by some 
paranoid sanitation code in luasandbox.

Is there a way to restore or export to Lua global namespace it in C++ 
somewhere before or after lua_pushcfunction(L, luaopen_lpeg) call?

I will appreciate any help.

Alexander Mashin