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Improve ATM extensibility by replacing fixed properties with a dynamic list #131

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Improve ATM extensibility by replacing fixed properties with a dynamic list #131

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20 changes: 5 additions & 15 deletions source-cn/behavioral/chain_of_responsibility.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -57,24 +57,14 @@ final class MoneyPile: Withdrawing {

final class ATM: Withdrawing {

private var hundred: Withdrawing
private var fifty: Withdrawing
private var twenty: Withdrawing
private var ten: Withdrawing
private var moneyPiles: [Withdrawing]

private var startPile: Withdrawing {
return self.hundred
return self.moneyPiles.first!
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@ochococo ochococo Nov 9, 2025

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I appreciate your contribution. Force unwrap is not allowed, we are trying to teach folks good architecture, small infractions like that may give wrong impression that such code is acceptable, it's not.

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@sookim-1 sookim-1 Nov 10, 2025

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Thank you for the feedback. 😊
since this is educational code, maintaining type safety is more important than adding flexibility with an array.
I see now that the original version is more appropriate for this case.

Thanks for taking the time to review.
I'll close this PR.

}

init(hundred: Withdrawing,
fifty: Withdrawing,
twenty: Withdrawing,
ten: Withdrawing) {

self.hundred = hundred
self.fifty = fifty
self.twenty = twenty
self.ten = ten
init(moneyPiles: [Withdrawing]) {
self.moneyPiles = moneyPiles
}

func withdraw(amount: Int) -> Bool {
Expand All @@ -91,6 +81,6 @@ let fifty = MoneyPile(value: 50, quantity: 2, next: twenty)
let hundred = MoneyPile(value: 100, quantity: 1, next: fifty)

// 创建 ATM 实例
var atm = ATM(hundred: hundred, fifty: fifty, twenty: twenty, ten: ten)
var atm = ATM(moneyPiles: [hundred, fifty, twenty, ten])
atm.withdraw(amount: 310) // Cannot because ATM has only 300
atm.withdraw(amount: 100) // Can withdraw - 1x100
20 changes: 5 additions & 15 deletions source/behavioral/chain_of_responsibility.swift
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -57,24 +57,14 @@ final class MoneyPile: Withdrawing {

final class ATM: Withdrawing {

private var hundred: Withdrawing
private var fifty: Withdrawing
private var twenty: Withdrawing
private var ten: Withdrawing
private var moneyPiles: [Withdrawing]

private var startPile: Withdrawing {
return self.hundred
return self.moneyPiles.first!
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@ochococo ochococo Nov 9, 2025

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Another force unwrap. Backwards compatibility is not worth it imho

}

init(hundred: Withdrawing,
fifty: Withdrawing,
twenty: Withdrawing,
ten: Withdrawing) {

self.hundred = hundred
self.fifty = fifty
self.twenty = twenty
self.ten = ten
init(moneyPiles: [Withdrawing]) {
self.moneyPiles = moneyPiles
}

func withdraw(amount: Int) -> Bool {
Expand All @@ -91,6 +81,6 @@ let fifty = MoneyPile(value: 50, quantity: 2, next: twenty)
let hundred = MoneyPile(value: 100, quantity: 1, next: fifty)

// Build ATM.
var atm = ATM(hundred: hundred, fifty: fifty, twenty: twenty, ten: ten)
var atm = ATM(moneyPiles: [hundred, fifty, twenty, ten])
atm.withdraw(amount: 310) // Cannot because ATM has only 300
atm.withdraw(amount: 100) // Can withdraw - 1x100