local serpent = grab('#158')
local function tableToLua(t)
  return "return "..serpent.block(t)
end

local function isSimpleTable(tbl, seen)
  if seen == nil then seen = {} end
  local seen = {}
  if seen[tbl] then return false end -- has cycles, not simple
  local t = type(tbl)
  if t == 'number' or t == 'string' then return true end
  if t ~= 'table' then return false end
  seen[tbl] = true
  for k, v in pairs(tbl) do
    if not isSimpleTable(k, seen)
      or not isSimpleTable(t, seen) then
        return false
    end
  end
end

local lines = {}
for k, v in pairs(_G) do
  if type(v) == 'number' then
    table.insert(lines, k..'='..tostring(v))
  elseif type(v) == 'string' then
    table.insert(lines, k..'='..('%q'):format(v))
  elseif type(v) == 'table' and isSimpleTable(v) then
    table.insert(lines, k..'='..tableToLua(v))
  end
end
return table.concat(lines, "\n")

Special snippet. Used for updating objects.