setmetatable()
#!/usr/bin/env lua t = { "foo", "bar", "baz" } print(t.__metatable) setmetatable(t, {}) setmetatable(t, nil) mt = {} mt.__metatable = function(x) end setmetatable(t, mt) setmetatable(t, nil)
で、
nil lua: ./2008112900.lua:15: cannot change a protected metatable