69 lines
2.3 KiB
Text
69 lines
2.3 KiB
Text
# wallet.ludic - the purse, its verbs, its facts and its save section
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export property MoneyChanged {
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before: int = 0
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after: int = 0
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}
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export state WalletState {
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wl_money: int = 0
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wl_changes: Queue<MoneyChanged> = wl_changes__new()
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}
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export function wallet_changes(wallet_st: WalletState) -> Queue<MoneyChanged> {
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return wallet_st.wl_changes
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}
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export function wallet_money(wallet_st: WalletState) -> int { return wallet_st.wl_money }
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export function wallet_can(wallet_st: WalletState, n: int) -> bool { return wallet_st.wl_money >= n }
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# the purse holds exactly n (a starting purse, a correction, the network's word)
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export function wallet_set(wallet_st: mut WalletState, n: int) -> void {
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if n == wallet_st.wl_money { return }
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var c = q_rec(wallet_changes(wallet_st))
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if c == null {
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@alloc_ok("past the ring: more of these in a frame than its records, then kept in it")
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c = new MoneyChanged
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q_ring_add(wallet_changes(wallet_st), c)
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}
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c.before = wallet_st.wl_money
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c.after = n
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wallet_st.wl_money = n
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q_push(wallet_changes(wallet_st), c)
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}
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export function wallet_earn(wallet_st: mut WalletState, n: int) -> void { wallet_set(wallet_st, wallet_st.wl_money + n) }
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# only what is there: false, and nothing spent, when it is not
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export function wallet_spend(wallet_st: mut WalletState, n: int) -> bool {
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if n > wallet_st.wl_money { return false }
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wallet_set(wallet_st, wallet_st.wl_money - n)
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return true
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}
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# a cost that happens whether or not it can be paid (a rescue, a fine); never below zero
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export function wallet_lose(wallet_st: mut WalletState, n: int) -> void { wallet_set(wallet_st, Math.max(wallet_st.wl_money - n, 0)) }
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export function wallet_reset(wallet_st: mut WalletState) -> void {
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wallet_st.wl_money = 0
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q_clear(wallet_changes(wallet_st))
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}
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export function wallet_save(wallet_st: WalletState) -> Val {
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let v = Value.object()
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sv_put_int(v, "money", wallet_st.wl_money)
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return v
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}
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export function wallet_load(wallet_st: mut WalletState, v: Val, version: int) -> void {
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wallet_st.wl_money = sv_int(v, "money", 0)
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q_clear(wallet_changes(wallet_st))
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}
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export function wallet_system() -> System {
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let s = system_new("wallet", PH_COMMIT)
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s.reset = fn wallet_reset
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s.save = fn wallet_save
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s.load = fn wallet_load
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return s
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}
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function wl_changes__new() -> Queue<MoneyChanged> { return queue_new("wallet.changes") }
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