kw actor

Actor       = "actor" Ident [ "sharded" "by" Ident ":" Type ] "{" { ActorMember } "}" ;

actor Session {
  var cart: Cart = Cart.empty()
  msg add(item: Item) { cart.push(item) }
  msg total() -> Money { cart.sum() }
}

let s = spawn Session()           // ActorRef<Session>
s.add(item) -> s.total() -> show(it)

@idle(ACCOUNT_IDLE)
actor Account sharded by id: AccountId {
  var balance: Money = Money.zero()
  @transient var hits: u64 = 0
  on activate { log.debug("account {id} up") }
  msg deposit(x: Money) { balance += x }
  msg balance() -> Money { balance }
}

Account(id).deposit(amount)