homework-jianmu/2.0/deps/lua/etc/strict.lua

35 lines
806 B
Lua

--
-- 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
mt.__declared = {}
mt.__newindex = function (t, n, v)
if 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