Merge pull request #24 from jaraco/feature/simple-series

All holidays observed after earlier holidays.

calendra/asia/china.py

@@ -93,10 +93,6 @@ class China(SeriesShiftMixin, ChineseNewYearCalendar):
     FIXED_HOLIDAYS = tuple(national_days)
 
     include_chinese_new_year_eve = True
-    series_requiring_shifts = ['Spring Festival', 'Ching Ming Festival',
-                               'Labour Day Holiday', 'Dragon Boat Festival',
-                               'Mid-Autumn Festival', 'New year',
-                               'National Day']
 
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)

calendra/asia/south_korea.py

@@ -19,7 +19,6 @@ class SouthKorea(SeriesShiftMixin, ChineseNewYearCalendar):
     chinese_new_year_eve_label = "Korean New Year's Day"
     include_chinese_second_day = True
     chinese_second_day_label = "Korean New Year's Day"
-    series_requiring_shifts = ["Korean New Year's Day", "Midautumn Festival"]
 
     def get_variable_days(self, year):
         days = super().get_variable_days(year)

calendra/core.py

@@ -7,6 +7,7 @@
 from datetime import date, timedelta, datetime
 from pathlib import Path
 import sys
+import functools
 
 import convertdate
 from dateutil import easter
@@ -232,7 +233,7 @@ def get_variable_days(self, year):  # noqa
                 date(year, 12, 26),
                 self.boxing_day_label,
                 indication="Day after Christmas",
-                observe_after=christmas
+                observe_after=christmas,
             )
             days.append(boxing_day)
         if self.include_ascension:
@@ -527,11 +528,6 @@ def get_islamic_holidays(self):  # noqa: C901
                           " to compute it. You'll have to add it manually.")
         return tuple(days)
 
-    def get_calendar_holidays(self, year):
-        self.series_requiring_shifts = [self.eid_al_fitr_label,
-                                        self.day_of_sacrifice_label]
-        return super().get_calendar_holidays(year)
-
 
 class CoreCalendar:
 
@@ -597,6 +593,7 @@ def get_holiday_label(self, day):
         day = cleaned_date(day)
         return {day: label for day, label in self.holidays(day.year)}.get(day)
 
+    @functools.lru_cache()
     def get_observed_date(self, holiday):
         """
         The date the holiday is observed for this calendar. If the holiday

calendra/europe/netherlands.py

@@ -2,6 +2,7 @@
 from ..core import WesternCalendar, SUN, ISO_SAT
 from ..core import SeriesShiftMixin
 from ..registry_tools import iso_register
+from ..core import Holiday
 
 
 @iso_register('NL')
@@ -15,7 +16,6 @@ class Netherlands(SeriesShiftMixin, WesternCalendar):
     include_whit_sunday = True
     include_whit_monday = True
     include_boxing_day = True
-    series_requiring_shifts = ["Carnival"]
 
     FIXED_HOLIDAYS = WesternCalendar.FIXED_HOLIDAYS + (
         (5, 5, "Liberation Day"),
@@ -120,11 +120,6 @@ class NetherlandsWithSchoolHolidays(Netherlands):
     Data source and regulating body:
     https://www.rijksoverheid.nl/onderwerpen/schoolvakanties/overzicht-schoolvakanties-per-schooljaar
     """
-    series_requiring_shifts = [
-        "Carnival", "Carnival holiday",
-        "Fall holiday", "Christmas holiday", "Spring holiday", "May holiday",
-        "Summer holiday"
-    ]
 
     def __init__(self, region, carnival_instead_of_spring=False, **kwargs):
         """ Set up a calendar incl. school holidays for a specific region
@@ -166,7 +161,13 @@ def get_fall_holidays(self, year):
             (start + timedelta(days=i), "Fall holiday") for i in range(n_days)
         ]
 
-    def get_christmas_holidays(self, year, in_december=True, in_january=True):
+    def get_christmas_holidays(self, year):
+        return [
+            Holiday._from_resolved_definition(defn, observance_shift=None)
+            for defn in self._get_christmas_holidays(year)
+        ]
+
+    def _get_christmas_holidays(self, year, in_december=True, in_january=True):
         """
         Return Christmas holidays
 
@@ -188,7 +189,7 @@ def get_christmas_holidays(self, year, in_december=True, in_january=True):
 
             if in_january:
                 dates.extend(
-                    self.get_christmas_holidays(year, in_december=False)
+                    self._get_christmas_holidays(year, in_december=False)
                 )
             return dates
 

calendra/europe/serbia.py

@@ -22,4 +22,3 @@ class Serbia(SeriesShiftMixin, OrthodoxCalendar):
     include_easter_sunday = True
     include_easter_monday = True
     include_christmas = False
-    series_requiring_shifts = ["Statehood Day"]

calendra/holiday.py

@@ -1,6 +1,5 @@
 import itertools
 from datetime import date, timedelta
-from typing import Optional, List
 
 from more_itertools import recipes
 
@@ -92,67 +91,29 @@ def _from_fixed_definition(cls, item):
         return item
 
     @classmethod
-    def _from_resolved_definition(cls, item):
+    def _from_resolved_definition(cls, item, **kwargs):
         """For backward compatibility, load Holiday object from a two-tuple
         or existing Holiday instance.
         """
         if isinstance(item, tuple):
-            item = Holiday(*item)
+            item = Holiday(*item, **kwargs)
         return item
 
 
 class SeriesShiftMixin:
     """
     "Series" holidays like the two Islamic Eid's or Chinese Spring Festival span
     multiple days. If one of these days encounters a non-zero observance_shift,
-    we need to apply that shift to all subsequent members of the series.
-
-    Packagin as a standalone Mixin ensure that the logic can be applied as
-    needed *after* any default shift is applied.
-    """
-    series_requiring_shifts: Optional[List[str]] = None
-    """
-    A list of all holiday labels that require series shifting to be applied.
+    apply that shift to all subsequent members of the series.
     """
 
     def get_calendar_holidays(self, year):
         """
-        The point at which any shift occurs is year-specific.
+        Ensure that all events are observed in the order indicated.
         """
         days = super().get_calendar_holidays(year)
-        series_shift = {series: None for series in self.series_requiring_shifts}
-        holidays = []
-        for holiday, label in days:
-            #
-            # Make a year-specific copy in case we have to attach a shift.
-            #
-            holiday = Holiday(holiday, label)
-            #
-            # For either Eid series, apply the shift to all days in the
-            # series after the first shift.
-            #
-            if label in series_shift:
-                shifted = self.get_observed_date(holiday)
-                if series_shift[holiday.name] is None and shifted.day != holiday.day:
-
-                    def observance_shift_for_series(holiday, calendar):
-                        """
-                        Taking an existing holiday, return a 'shifted' day based
-                        on delta in the current year's closure.
-                        """
-                        return holiday + delta
-
-                    delta = date(shifted.year, shifted.month, shifted.day) - \
-                        date(holiday.year, holiday.month, holiday.day)
-                    #
-                    # Learn the observance_shift for all subsequent days in the
-                    # series.
-                    #
-                    series_shift[holiday.name] = observance_shift_for_series
-                elif series_shift[holiday.name] is not None:
-                    #
-                    # Apply the learned observance_shift.
-                    #
-                    holiday.observance_shift = series_shift[holiday.name]
-            holidays.append(holiday)
+        holidays = sorted(map(Holiday._from_resolved_definition, days))
+        from more_itertools import pairwise
+        for a, b in pairwise(holidays):
+            b.observe_after = a
         return holidays