Re: Deprecating setfenv()

[Peter Odding <peter@...>]

I've always considered package.seeall an ugly solution because it makes
module tables shadow the globals table and I'm pretty sure I'm not
the only one [1]. Therefor I've always used the following code:

module(..., function(_M)
  setfenv(3, setmetatable({}, {
    __index = function(_, k) return _M[k] or _G[k] end,
    __newindex = function(_, k, v) _M[k] = v end,
  }))
end)

Can anyone tell me whether there is a way to accomplish the goal of
separating the module environment from the module table in Lua 5.2.0
(work1) without using the debug library? The reason I (and others)
insist on not using the debug library is because it's labeled
`debug' and the reference manual explains the name very clearly:

> You should exert care when using this library. The functions provided
> here should be used exclusively for debugging and similar tasks, such
> as profiling. Please resist the temptation to use them as a usual
> programming tool: they can be very slow. Moreover, several of these
> functions violate some assumptions about Lua code (e.g., that
> variables local to a function cannot be accessed from outside or that
> userdata metatables cannot be changed by Lua code) and therefore can
> compromise otherwise secure code.

To further clarify my position, I wouldn't mind if the use of setfenv() 
was discouraged by moving it from the globals to a separate library like 
`reflect' or `introspect' (which the user would have to explicitly 
require() for all I care) but I would hate for setfenv() to end up in 
the debug library, where it's pretty much off limits to anything except 
hacks and debuggers.

 - Peter Odding

[1] http://lua-users.org/wiki/LuaModuleFunctionCritiqued