Lexical environments

[Dirk Laurie <dpl@...>]

The Unofficial FAQ says:

--[[
8.2 What are the new Lua 5.2 features?
8.2.1 Lexical Environments

These define a block in which all global accesses happen in a given environment (which can be a table or userdata):

t = {}
in t do
    x = 10
    y = 20
end
=> t == {x=10,y=10}
--]]

but the recently released alpha version of 5.2 does not allow the construct,
neither the BNF specification nor the 'lua' executable.

Considered but not accepted?  Planned but not yet implemented?

Dirk