Is there anyway to "shallow" clone a Lua closure using C API?

[Chaos Wang <chaoslawful@...>]

Hi,


I wonder if there is any way to "shallow" clone a Lua closure in C. By 
say "shallow" cloning I mean the clone and original Lua closure share 
the same Proto and upvalues, but can have different environment table.

I tried lua_pushvalue(), but it only make a direct reference for GC-able 
objects, which include closures.

Thanks!