--

-- strict.lua

-- checks uses of undeclared global variables

-- All global variables must be 'declared' through a regular assignment

-- (even assigning nil will do) in a main chunk before being used

-- anywhere or assigned to inside a function.

--

local getinfo, error, rawset, rawget = debug.getinfo, error, rawset, rawget

local mt = getmetatable(_G)

if mt == nil then

mt = {}

setmetatable(_G, mt)

end

mt.__declared = {}

local function what ()

local d = getinfo(3, "S")

return d and d.what or "C"

end

mt.__newindex = function (t, n, v)

if not mt.__declared[n] then

if w ~= "main" and w ~= "C" then

error("assign to undeclared variable '"..n.."'", 2)

end

mt.__declared[n] = true

end

rawset(t, n, v)

end

mt.__index = function (t, n)

error("variable '"..n.."' is not declared", 2)

end

return rawget(t, n)

end