31 lines
731 B
Python
31 lines
731 B
Python
from typing import TypeVar, cast
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from demo_stubs import CHF, EUR, USD, Currency, Price, Discount
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T = TypeVar("T", bound=Currency)
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def apply_discount(amount: Price[T], discount: Discount) -> Price[T]:
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return cast(Price[T], (1.0 - discount) * amount)
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a1 = cast(Price[EUR], 3.2)
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a2 = cast(Price[USD], 10.4)
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r1 = cast(Discount, 0.2)
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print(apply_discount(a1, r1))
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print(apply_discount(a2, r1))
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a3 = a1 + a1
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a4 = a1 + a2 # cannot add euros and dollars
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a3 = a2 # cannot change variable type
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dyn_price = float(input("Price (CHF): "))
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dyn_discount = float(input("Discount (0.0-1.0): "))
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discounted = apply_discount(
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cast(Price[CHF], dyn_price),
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cast(Discount, dyn_discount),
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)
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print(f"Discounted: CHF {discounted}")
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