Extended Enum classes for the Python 3 enum module
Project description
extenum
Extended Enum classes for the Python 3 enum module.
The enum module was added since 3.4. That’s good enough for simple use. The extenum is strongly inspired by Java Enum style described in Effective Java and privides additional feature.
How to install
NOTE: extenum supports Python 3 only.
$ pip install extenum
ConstantSpecificEnum
ConstantSpecificEnum class is inherited the standard Enum class and provides the feature of constant specific method and function overloading for Enum members.
Read Effective Java for more detail.
Constant specific method implementation
Let’s try to create Enum class with ConstantSpecificEnum. To use method as function overloading, create the registory with RegisterFactory for target Enum class.
>>> from extenum import ConstantSpecificEnum, RegisterFactory
>>> class Operation(ConstantSpecificEnum):
... PLUS = '+'
... MINUS = '-'
... TIMES = '*'
... DIVIDE = '/'
...
... overload = RegisterFactory()
...
... @overload.register(PLUS)
... def apply(self, x, y):
... return x + y
...
... @overload.register(MINUS)
... def apply(self, x, y):
... return x - y
...
... @overload.register(TIMES)
... def apply(self, x, y):
... return x * y
...
... @overload.register(DIVIDE)
... def apply(self, x, y):
... return x / y
...
>>> for name, const in Operation.__members__.items():
... print(name, ':', const.apply(2, 4))
...
PLUS : 6
MINUS : -2
TIMES : 8
DIVIDE : 0.5
Strategy enum pattern
The strategy enum is more complex pattern based on constant specific method.
>>> from extenum import ConstantSpecificEnum, RegisterFactory
>>> class PayrollDay(ConstantSpecificEnum):
...
... class PayType(ConstantSpecificEnum):
... WEEKDAY = 1
... WEEKEND = 2
...
... overload = RegisterFactory()
...
... @overload.register(WEEKDAY)
... def overtime_pay(self, hours, pay_rate):
... return 0 if hours <= 8 else (hours - 8) * pay_rate / 2
...
... @overload.register(WEEKEND)
... def overtime_pay(self, hours, pay_rate):
... return hours * pay_rate / 2
...
... def pay(self, hours_worked, pay_rate):
... base_pay = hours_worked * pay_rate
... overtime_pay = self.overtime_pay(hours_worked, pay_rate)
... return base_pay + overtime_pay
...
... MONDAY = PayType.WEEKDAY
... TUESDAY = PayType.WEEKDAY
... WEDNESDAY = PayType.WEEKDAY
... THURSDAY = PayType.WEEKDAY
... FRIDAY = PayType.WEEKDAY
... SATURDAY = PayType.WEEKEND
... SUNDAY = PayType.WEEKEND
...
... def pay(self, hours_worked, pay_rate):
... return self.value.pay(hours_worked, pay_rate)
...
>>> PayrollDay.MONDAY.pay(10, 1000.0)
11000.0
>>> PayrollDay.WEDNESDAY.pay(8, 1000.0)
8000.0
>>> PayrollDay.SATURDAY.pay(10, 1000.0)
15000.0
>>> PayrollDay.SUNDAY.pay(8, 1000.0)
12000.0
ChangeLog
0.5.0 (2015-03-01)
first release
Project details
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