do(
  def(x, object(
    "c", 0,
    "gc", ->{c},
    "sc", ->{value, =(c, value)},
    "inc", ->{=(c, +(c, 1))}
  )),
  def(y, child(x)),
  print(y.sc(5)),
  print(y.c),
  print(x.c)
)