Should nested classes in an Enum be Enum members?
Ethan Furman
ethan at stoneleaf.us
Thu Jun 28 21:33:31 EDT 2018
On 06/28/2018 05:58 PM, Ben Finney wrote:
> So I remain dumbfounded as to why anyone would want a class to *both* be
> an enumerated type, *and* have callable attributes in its API.
Perhaps I am using Enum incorrectly, but here is my FederalHoliday Enum. Note that date(), next_business_day, and
year() are all callables. The AutoEnum parent assigns values from 1 to n for each member. It's at Stackoverflow [1] if
you'd like up- or down-vote it. ;)
---
class FederalHoliday(AutoEnum):
NewYear = "First day of the year.", 'absolute', Month.JANUARY, 1
MartinLutherKingJr = "Birth of Civil Rights leader.", 'relative', Month.JANUARY, Weekday.MONDAY, 3
President = "Birth of George Washington", 'relative', Month.FEBRUARY, Weekday.MONDAY, 3
Memorial = "Memory of fallen soldiers", 'relative', Month.MAY, Weekday.MONDAY, 5
Independence = "Declaration of Independence", 'absolute', Month.JULY, 4
Labor = "American Labor Movement", 'relative', Month.SEPTEMBER, Weekday.MONDAY, 1
Columbus = "Americas discovered", 'relative', Month.OCTOBER, Weekday.MONDAY, 2
Veterans = "Recognition of Armed Forces service", 'relative', Month.NOVEMBER, 11, 1
Thanksgiving = "Day of Thanks", 'relative', Month.NOVEMBER, Weekday.THURSDAY, 4
Christmas = "Birth of Jesus Christ", 'absolute', Month.DECEMBER, 25
def __init__(self, doc, type, month, day, occurance=None):
self.__doc__ = doc
self.type = type
self.month = month
self.day = day
self.occurance = occurance
def date(self, year):
"returns the observed date of the holiday for `year`"
if self.type == 'absolute' or isinstance(self.day, int):
holiday = Date(year, self.month, self.day)
if Weekday(holiday.isoweekday()) is Weekday.SUNDAY:
holiday = holiday.replace(delta_day=1)
return holiday
days_in_month = days_per_month(year)
target_end = self.occurance * 7 + 1
if target_end > days_in_month[self.month]:
target_end = days_in_month[self.month]
target_start = target_end - 7
target_week = list(xrange(start=Date(year, self.month, target_start), step=one_day, count=7))
for holiday in target_week:
if Weekday(holiday.isoweekday()) is self.day:
return holiday
@classmethod
def next_business_day(cls, date, days=1):
"""
Return the next `days` business day from date.
"""
holidays = cls.year(date.year)
years = set([date.year])
while days > 0:
date = date.replace(delta_day=1)
if date.year not in years:
holidays.extend(cls.year(date.year))
years.add(date.year)
if Weekday(date.isoweekday()) in (Weekday.SATURDAY, Weekday.SUNDAY) or date in holidays:
continue
days -= 1
return date
@classmethod
def year(cls, year):
"""
Return a list of the actual FederalHoliday dates for `year`.
"""
holidays = []
for fh in cls:
holidays.append(fh.date(year))
return holidays
--
~Ethan~
[1] https://stackoverflow.com/a/22594360/208880
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