-- -- 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 mt = getmetatable(_G) if mt == nil then mt = {} setmetatable(_G, mt) end __STRICT = true mt.__declared = {} mt.__newindex = function (t, n, v) if __STRICT and not mt.__declared[n] then local w = debug.getinfo(2, "S").what 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) if not mt.__declared[n] and debug.getinfo(2, "S").what ~= "C" then error("variable '"..n.."' is not declared", 2) end return rawget(t, n) end function global(...) for _, v in ipairs{...} do mt.__declared[v] = true end end