ohgodplzkillit.lua

local grandparent = { a = 1, b = 2, c = 3 }

local parent = { a = 4, b = 5 }
setmetatable(parent, { __index = grandparent })

local child = { a = 7 }
setmetatable(child, { __index = parent })

local function mpairs(t)
  local returned = {}
  local function next_family(_,k)
    local v
    repeat
      k,v = next(t,k)
      if not k then break end
    until not returned[k]
    if k then
      returned[k] = true
      return k,v
    end
    local mt = getmetatable(t)
    if mt and type(mt.__index) == 'table' then
      t = mt.__index
      return next_family(nil,nil)
    end
    return nil
  end
  return next_family
end

for k,v in mpairs(child) do print(k,v) end

Somebody required an iterator with the properties that: it will traverse a table, including all inherited properties as well. So I built this: it traverse a table, then when finished, ascends to the next parent up and traverses it too. On the way, it skips any keys which were present somewhere up the line (so they're not getting inherited).

I can't imagine why he really needs this, but here you have it. An ugly-ass iterator.