-- Assume double is a language construct that doubles a number

State {
  Tc = ?
  Ctx = nil
  C = double (call/cc k . suc k)
  E = []
  K = halt
}

State {
  Tc = ?
  Ctx = nil
  C = x * 2
  E  = [x = call/cc k . suc k]
  K = halt
}