+function set_function_metatable()
+ local mt = {};
+ function mt.__index(f, upvalue)
+ local i, name, value = 0;
+ repeat
+ i = i + 1;
+ name, value = debug.getupvalue(f, i);
+ until name == upvalue or name == nil;
+ return value;
+ end
+ function mt.__newindex(f, upvalue, value)
+ local i, name = 0;
+ repeat
+ i = i + 1;
+ name = debug.getupvalue(f, i);
+ until name == upvalue or name == nil;
+ if name then
+ debug.setupvalue(f, i, value);
+ end
+ end
+ debug.setmetatable(function() end, mt);
+end
+