function compareTables(t1, t2)
  if type(t1) ~= 'table' or type(t2) ~= 'table' then
    return t1 == t2
  end
  
  -- compare common elements, check for extra elements in t1
  for k, v in pairs(t1) do
    local v2 = t2[k]
    if not compareTables(v, v2) then return false end
  end
  
  -- check for extra elements in t2
  for k, v in pairs(t2) do
    local v1 = t1[k]
    if v1 == nil then return false end
  end
  
  -- all matched, tables are equal
  return true
end