Created
March 24, 2014 13:30
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Verify the usage of global variables previously undeclared from http://www.lua.org/extras/5.2/strict.lua.
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-- 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. | |
-- distributed under the Lua license: http://www.lua.org/license.html | |
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 | |
local w = 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 what() ~= "C" then | |
error("variable '"..n.."' is not declared", 2) | |
end | |
return rawget(t, n) | |
end |
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