jonas
2764849943
Port the finite state machine from "Programming Game AI by Example" chapter 2: BaseGameEntity, a generic State[T]/StateMachine[T] pair (Go generics standing in for the book's C++ templates), and a Miner that cycles through digging, banking, sleeping, and drinking states. VisitBankAndDepositGold, GoHomeAndSleepTilRested, and QuenchThirst are original implementations based on the book's written behavior description, since their C++ source wasn't available. Includes a runnable demo in main.go.
62 lines
2.0 KiB
Go
62 lines
2.0 KiB
Go
package westworld
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import (
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"fmt"
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"sync"
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)
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// visitBankAndDepositGold is the Go version of the (not yet pasted)
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// singleton class VisitBankAndDepositGold from the book. Same
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// pattern as enterMineAndDigForNugget: unexported type, one shared
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// instance, reached only through the function below.
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type visitBankAndDepositGold struct{}
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var (
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visitBankAndDepositGoldInstance *visitBankAndDepositGold
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visitBankAndDepositGoldOnce sync.Once
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)
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// VisitBankAndDepositGold is the Go stand-in for
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// "VisitBankAndDepositGold::Instance()".
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func VisitBankAndDepositGold() *visitBankAndDepositGold {
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visitBankAndDepositGoldOnce.Do(func() {
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visitBankAndDepositGoldInstance = &visitBankAndDepositGold{}
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})
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return visitBankAndDepositGoldInstance
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}
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var _ State[Miner] = (*visitBankAndDepositGold)(nil)
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// The book hasn't shown us this state's real code, so this is our
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// own implementation based purely on its written description: "the
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// miner will walk to the bank and deposit any nuggets he is
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// carrying. If he then considers himself wealthy enough, he will
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// change state to GoHomeAndSleepTilRested. Otherwise he will change
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// state to EnterMineAndDigForNugget."
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// Enter sends the miner to the bank, if he isn't there already.
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func (s *visitBankAndDepositGold) Enter(m *Miner) {
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if m.Location() != bank {
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fmt.Printf("\n%s: Goin' to the bank. Yes siree", GetNameOfEntity(m.ID()))
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m.ChangeLocation(bank)
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}
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}
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// Execute deposits whatever gold the miner is carrying, then decides
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// where to go next based on how wealthy that leaves him.
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func (s *visitBankAndDepositGold) Execute(m *Miner) {
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m.TransferGoldToBank()
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fmt.Printf("\n%s: Depositing gold. Total savings now: %d", GetNameOfEntity(m.ID()), m.moneyInBank)
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if m.RichEnough() {
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m.ChangeState(GoHomeAndSleepTilRested())
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} else {
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m.ChangeState(EnterMineAndDigForNugget())
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}
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}
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// Exit announces that the miner is leaving the bank.
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func (s *visitBankAndDepositGold) Exit(m *Miner) {
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fmt.Printf("\n%s: Leavin' the bank", GetNameOfEntity(m.ID()))
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}
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