Comment by vkka

Lua gives you means to build your object system anyway you want. A trivial example to protect a table below:

  local p = { x = 1, y = 2 }
  print( p.x, p.y )
  
  setmetatable( p,
  {
      __newindex = function() assert( false ) end,
      __index = function() assert( false ) end
  } )
  
  print( p.z )    -- you get assertion failure
  p.k = 12        -- you get assertion failure too