[Python-checkins] python/nondist/sandbox/datetime datetime.py,1.130,1.131 doc.txt,1.75,1.76

[tim_one@users.sourceforge.net]

Update of /cvsroot/python/python/nondist/sandbox/datetime
In directory sc8-pr-cvs1:/tmp/cvs-serv25945

Modified Files:
	datetime.py doc.txt 
Log Message:
Inlined a timezone conversion routine that turned out to be called only
once.  Updated the docs.  The hoped-for treatment of DST endcases
remains unclear.


Index: datetime.py
===================================================================
RCS file: /cvsroot/python/python/nondist/sandbox/datetime/datetime.py,v
retrieving revision 1.130
retrieving revision 1.131
diff -C2 -d -r1.130 -r1.131
*** datetime.py	31 Dec 2002 05:58:02 -0000	1.130
--- datetime.py	31 Dec 2002 15:56:31 -0000	1.131
***************
*** 1618,1646 ****
                           "inconsistent results; cannot convert")
  
-     def _finish_astimezone(self, other, otoff):
-         # If this is the first hour of DST, it may be a local time that
-         # doesn't make sense on the local clock, in which case the naive
-         # hour before it (in standard time) is equivalent and does make
-         # sense on the local clock.  So force that.
-         alt = other - _HOUR
-         altoff = alt.utcoffset()
-         if altoff is None:
-             self._inconsistent_utcoffset_error()
-         # Are alt and other really the same time?  alt == other iff
-         # alt - altoff == other - otoff, iff
-         # (other - _HOUR) - altoff = other - otoff, iff
-         # otoff - altoff == _HOUR
-         diff = otoff - altoff
-         if diff == _HOUR:
-             return alt      # use the local time that makes sense
- 
-         # There's still a problem with the unspellable (in local time)
-         # hour after DST ends.
-         if self == other:
-             return other
-         # Else there's no way to spell self in zone other.tz.
-         raise ValueError("astimezone():  the source datetimetz can't be "
-                          "expressed in the target timezone's local time")
- 
      def astimezone(self, tz):
          _check_tzinfo_arg(tz)
--- 1618,1621 ----
***************
*** 1679,1683 ****
              if otoff is None:
                  self._inconsistent_utcoffset_error()
!         return self._finish_astimezone(other, otoff)
  
      def isoformat(self, sep='T'):
--- 1654,1682 ----
              if otoff is None:
                  self._inconsistent_utcoffset_error()
! 
!         # If this is the first hour of DST, it may be a local time that
!         # doesn't make sense on the local clock, in which case the naive
!         # hour before it (in standard time) is equivalent and does make
!         # sense on the local clock.  So force that.
!         alt = other - _HOUR
!         altoff = alt.utcoffset()
!         if altoff is None:
!             self._inconsistent_utcoffset_error()
!         # Are alt and other really the same time?  alt == other iff
!         # alt - altoff == other - otoff, iff
!         # (other - _HOUR) - altoff = other - otoff, iff
!         # otoff - altoff == _HOUR
!         diff = otoff - altoff
!         if diff == _HOUR:
!             return alt      # use the local time that makes sense
! 
!         # There's still a problem with the unspellable (in local time)
!         # hour after DST ends.
!         if self == other:
!             return other
!         # Else there's no way to spell self in zone other.tz.
!         raise ValueError("astimezone():  the source datetimetz can't be "
!                          "expressed in the target timezone's local time")
! 
  
      def isoformat(self, sep='T'):

Index: doc.txt
===================================================================
RCS file: /cvsroot/python/python/nondist/sandbox/datetime/doc.txt,v
retrieving revision 1.75
retrieving revision 1.76
diff -C2 -d -r1.75 -r1.76
*** doc.txt	30 Dec 2002 19:43:21 -0000	1.75
--- doc.txt	31 Dec 2002 15:56:31 -0000	1.76
***************
*** 3,8 ****
  - The Python implementation is missing docstrings in many places.
  
- - LaTeXize the docs.
- 
  
  CLOSED
--- 3,6 ----
***************
*** 834,840 ****
  tzinfo methods interpret dt as being in local time, and not need to worry
  about objects in other timezones.
- XXX That isn't always true yet:  datetimetz.astimezone(tz) can pass
- XXX a datetimetz with a "foreign" tzinfo to a self.tzinfo method.  This
- XXX needs to be repaired.
  
  Example tzinfo classes:
--- 832,835 ----
***************
*** 1161,1169 ****
      tz.utcoffset(self) does not return None, the date and time fields
      are adjusted so that the result is local time in timezone tz,
!     representing the same UTC time as self.  self.astimezone(tz) is then
!     equivalent to
!         (self - (self.utcoffset() - tz.utcoffset(self)).replace(tzinfo=tz)
!     where the result of tz.uctcoffset(self) is coerced to a timedelta if
!     needed.
  
    - timetuple()
--- 1156,1164 ----
      tz.utcoffset(self) does not return None, the date and time fields
      are adjusted so that the result is local time in timezone tz,
!     representing the same UTC time as self.
!     XXX The treatment of endcases remains unclear:  for DST-aware
!     XXX classes, one hour per year has two spellings in local time, and
!     XXX another hour has no spelling in local time.
!     
  
    - timetuple()