42 lines
928 B
Lua
42 lines
928 B
Lua
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--
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-- strict.lua
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-- checks uses of undeclared global variables
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-- All global variables must be 'declared' through a regular assignment
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-- (even assigning nil will do) in a main chunk before being used
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-- anywhere or assigned to inside a function.
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--
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local getinfo, error, rawset, rawget = debug.getinfo, error, rawset, rawget
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local mt = getmetatable(_G)
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if mt == nil then
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mt = {}
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setmetatable(_G, mt)
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end
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mt.__declared = {}
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local function what ()
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local d = getinfo(3, "S")
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return d and d.what or "C"
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end
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mt.__newindex = function (t, n, v)
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if not mt.__declared[n] then
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local w = what()
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if w ~= "main" and w ~= "C" then
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error("assign to undeclared variable '"..n.."'", 2)
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end
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mt.__declared[n] = true
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end
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rawset(t, n, v)
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end
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mt.__index = function (t, n)
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if not mt.__declared[n] and what() ~= "C" then
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error("variable '"..n.."' is not declared", 2)
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end
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return rawget(t, n)
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end
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