globals _AddSlotsIfAbsent: (| bankAccount <- (). account <- (). stockAccount <- (). stock <- (). |) bankAccount: (| parent* = traits clonable. dollars <- 200. deposit: x = (dollars + x). withdraw: x = (dollars: (0 max: dollars - x)). |) bankAccount dollars ==> 200 bankAccount deposit: 50 ==> 250 bankAccount withdraw: 100 bankAccount dollars ==> 150 bankAccount withdraw: 200 bankAccount dollars ==> 0 account: bankAccount copy account deposit: 500 account dollars ==> 500 bankAccout dollars ==> 0 # プロトタイプのスロットには影響なし。 stockAccount: bankAccount copy stockAccount _AddSlots: (| numShares <- 10. pricePerShare <- 30. dollars = (numShares * pricePerShare). dollars: x = (numShares: x / pricePerShare). |) stockAccount dollars ==> 300 stockAccount dollars: 150 stockAccount dollars ==> 150 stockAccount numShares ==> 5 # 株数値が変更されている。 stock: stockAccount copy stock dollars: 600 stock numShares ==> 20 stock deposit: 60 stock dollars ==> 660 stock numShares ==> 20
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