SF 658405: calendar.py to rely on the datetime module instead of the time
module.
The code is shorter, more readable, faster, and dramatically increases the
range of acceptable dates.
Also, used the floor division operator in leapdays().
diff --git a/Doc/lib/libcalendar.tex b/Doc/lib/libcalendar.tex
index 222e2db..bf0c85b 100644
--- a/Doc/lib/libcalendar.tex
+++ b/Doc/lib/libcalendar.tex
@@ -15,10 +15,12 @@
week to Sunday (6) or to any other weekday. Parameters that specify
dates are given as integers.
-Most of these functions rely on the platform provided \function{mktime()}.
-Therefore, valid argument values may vary from system to system.
-On Unix, valid years are typically between \code{1970} and \code{2037},
-but may be work between \code{1902} and \code{2037}.
+Most of these functions rely on the \module{datetime} module which
+uses an idealized calendar, the current Gregorian calendar indefinitely
+extended in both directions. This matches the definition of the
+"proleptic Gregorian" calendar in Dershowitz and Reingold's book
+"Calendrical Calculations", where it's the base calendar for all
+computations.
\begin{funcdesc}{setfirstweekday}{weekday}
Sets the weekday (\code{0} is Monday, \code{6} is Sunday) to start
diff --git a/Lib/calendar.py b/Lib/calendar.py
index 3f9b7ba..365ca26 100644
--- a/Lib/calendar.py
+++ b/Lib/calendar.py
@@ -5,10 +5,7 @@
Sunday as the last (the European convention). Use setfirstweekday() to
set the first day of the week (0=Monday, 6=Sunday)."""
-# Revision 2: uses functions from built-in time module
-
-# Import functions and variables from time module
-from time import localtime, mktime, strftime
+import datetime
__all__ = ["error","setfirstweekday","firstweekday","isleap",
"leapdays","weekday","monthrange","monthcalendar",
@@ -35,7 +32,7 @@
self.format = format
def __getitem__(self, i):
- data = [strftime(self.format, (2001, j, 1, 12, 0, 0, 1, 1, 0))
+ data = [datetime.date(2001, j, 1).strftime(self.format)
for j in range(1, 13)]
data.insert(0, "")
return data[i]
@@ -49,7 +46,7 @@
def __getitem__(self, i):
# January 1, 2001, was a Monday.
- data = [strftime(self.format, (2001, 1, j+1, 12, 0, 0, j, j+1, 0))
+ data = [datetime.date(2001, 1, j+1).strftime(self.format)
for j in range(7)]
return data[i]
@@ -89,14 +86,12 @@
Assume y1 <= y2."""
y1 -= 1
y2 -= 1
- return (y2/4 - y1/4) - (y2/100 - y1/100) + (y2/400 - y1/400)
+ return (y2//4 - y1//4) - (y2//100 - y1//100) + (y2//400 - y1//400)
def weekday(year, month, day):
"""Return weekday (0-6 ~ Mon-Sun) for year (1970-...), month (1-12),
day (1-31)."""
- secs = mktime((year, month, day, 0, 0, 0, 0, 0, 0))
- tuple = localtime(secs)
- return tuple[6]
+ return datetime.date(year, month, day).weekday()
def monthrange(year, month):
"""Return weekday (0-6 ~ Mon-Sun) and number of days (28-31) for
@@ -213,17 +208,12 @@
return s[:-l] + '\n'
EPOCH = 1970
+_EPOCH_ORD = datetime.date(EPOCH, 1, 1).toordinal()
+
def timegm(tuple):
"""Unrelated but handy function to calculate Unix timestamp from GMT."""
year, month, day, hour, minute, second = tuple[:6]
- assert year >= EPOCH
- assert 1 <= month <= 12
- days = 365*(year-EPOCH) + leapdays(EPOCH, year)
- for i in range(1, month):
- days = days + mdays[i]
- if month > 2 and isleap(year):
- days = days + 1
- days = days + day - 1
+ days = datetime.date(year, month, day).toordinal() - _EPOCH_ORD
hours = days*24 + hour
minutes = hours*60 + minute
seconds = minutes*60 + second
diff --git a/Misc/NEWS b/Misc/NEWS
index 5cc62bf..a9e3803 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -443,6 +443,10 @@
Library
-------
+- calendar.py now depends on the new datetime module rather than
+ the time module. As a result, the range of allowable dates
+ has been increased.
+
- pdb has a new 'j(ump)' command to select the next line to be
executed.