43 lines
1.2 KiB
Python
43 lines
1.2 KiB
Python
# strategy_best.py
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# Strategy pattern -- function-based implementation
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# selecting best promotion from static list of functions
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"""
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>>> joe = Customer('John Doe', 0)
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>>> ann = Customer('Ann Smith', 1100)
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>>> cart = [LineItem('banana', 4, .5),
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... LineItem('apple', 10, 1.5),
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... LineItem('watermelon', 5, 5.0)]
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>>> banana_cart = [LineItem('banana', 30, .5),
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... LineItem('apple', 10, 1.5)]
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>>> big_cart = [LineItem(str(item_code), 1, 1.0)
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... for item_code in range(10)]
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# tag::STRATEGY_BEST_TESTS[]
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>>> Order(joe, big_cart, best_promo) # <1>
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<Order total: 10.00 due: 9.30>
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>>> Order(joe, banana_cart, best_promo) # <2>
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<Order total: 30.00 due: 28.50>
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>>> Order(ann, cart, best_promo) # <3>
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<Order total: 42.00 due: 39.90>
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# end::STRATEGY_BEST_TESTS[]
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"""
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from strategy import Customer, LineItem, Order
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from strategy import fidelity_promo, bulk_item_promo, large_order_promo
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# tag::STRATEGY_BEST[]
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promos = [fidelity_promo, bulk_item_promo, large_order_promo] # <1>
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def best_promo(order) -> float: # <2>
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"""Select best discount available
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"""
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return max(promo(order) for promo in promos) # <3>
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# end::STRATEGY_BEST[]
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