setfenv on userdata???

[Chris Marrin <chris@...>]

I see in 5.1-work6 that you can now set environments not only on both C 
and Lua functions, but also on userdatas. But I don't see anywhere in 
the code where this environment is being used. What can you do with this 
environment? Does it get used when you make metamethod calls with this 
userdata? Or is it just there so it can be retrieved or something?

--
chris marrin              ,""$, "As a general rule,don't solve puzzles
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