53 lines
1.5 KiB
Lua
Executable File
53 lines
1.5 KiB
Lua
Executable File
require 'classlib'
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class.Account()
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function Account:__init(initial)
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self.balance = initial or 0
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end
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function Account:deposit(amount)
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self.balance = self.balance + amount
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end
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function Account:withdraw(amount)
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self.balance = self.balance - amount
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end
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function Account:getbalance()
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return self.balance
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end
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class.NamedAccount(shared(Account)) -- shared Account base
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function NamedAccount:__init(name, initial)
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self.Account:__init(initial)
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self.name = name or 'anonymous'
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end
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class.LimitedAccount(shared(Account)) -- shared Account base
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function LimitedAccount:__init(limit, initial)
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self.Account:__init(initial)
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self.limit = limit or 0
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end
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function LimitedAccount:withdraw(amount)
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if self:getbalance() - amount < self.limit then
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error 'Limit exceeded'
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else
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self.Account:withdraw(amount)
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end
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end
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class.NamedLimitedAccount(NamedAccount, LimitedAccount)
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function NamedLimitedAccount:__init(name, limit, initial)
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self.Account:__init(initial)
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self.NamedAccount:__init(name)
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self.LimitedAccount:__init(limit)
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end
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-- widthdraw() disambiguated to the limit-checking version
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function NamedLimitedAccount:withdraw(amount)
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return self.LimitedAccount:withdraw(amount)
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end
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myNLAccount = NamedLimitedAccount('John', 0.00, 10.00)
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myNLAccount:deposit(2.00)
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print('balance now', myNLAccount:getbalance()) --> 12.00
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myNLAccount:withdraw(1.00)
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print('balance now', myNLAccount:getbalance()) --> 11.00
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--myNLAccount:withdraw(15.00) --> error, limit exceeded
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