python · akeeman · Jan 5, 2018 · Jan 5, 2018 · Jan 5, 2018 · Jan 5, 2018
diff --git a/Doc/library/datetime.rst b/Doc/library/datetime.rst
@@ -861,7 +861,6 @@ Other constructors, all class methods:
 
   .. versionadded:: 3.7
 
-
 .. classmethod:: datetime.fromisocalendar(year, week, day)
 
    Return a :class:`datetime` corresponding to the ISO calendar date specified
@@ -871,15 +870,20 @@ Other constructors, all class methods:
 
    .. versionadded:: 3.8
 
-.. classmethod:: datetime.strptime(date_string, format)
+.. classmethod:: datetime.strptime(date_string, format, infos=None)
 
    Return a :class:`.datetime` corresponding to *date_string*, parsed according to
    *format*.  This is equivalent to ``datetime(*(time.strptime(date_string,
    format)[0:6]))``. :exc:`ValueError` is raised if the date_string and format
    can't be parsed by :func:`time.strptime` or if it returns a value which isn't a
    time tuple. For a complete list of formatting directives, see
    :ref:`strftime-strptime-behavior`.
+   To interpret a timezone name (`%Z`), provide a converter with the *infos*
+   argument that accepts a tz naive :class:`datetime` object and the tz
+   name string. It should return a :class:`tzinfo` object.
 
+   .. versionchanged:: 3.9
+      Added the *infos* argument.
 
 
 Class attributes:

diff --git a/Doc/whatsnew/3.9.rst b/Doc/whatsnew/3.9.rst
@@ -0,0 +1,8 @@
+Changes in the Python API
+-------------------------
+
+* :meth:`datetime.strptime` now accepts an optional 3rd parameter
+  `infos`. It accepts a callable or mapping that converts a timezone name to a
+  tzinfo object. For example ``datetime.strptime("2018-01-05 13:10:00 CET",
+  "%Y-%m-%d %H:%M:%S %Z", lambda dt, tzname: ...)``. It is used to interpret
+  the timezone name given by `%Z`.
diff --git a/Lib/_strptime.py b/Lib/_strptime.py
@@ -562,7 +562,7 @@ def _strptime_time(data_string, format="%a %b %d %H:%M:%S %Y"):
     tt = _strptime(data_string, format)[0]
     return time.struct_time(tt[:time._STRUCT_TM_ITEMS])
 
-def _strptime_datetime(cls, data_string, format="%a %b %d %H:%M:%S %Y"):
+def _strptime_datetime(cls, data_string, format="%a %b %d %H:%M:%S %Y", infos=None):
     """Return a class cls instance based on the input string and the
     format string."""
     tt, fraction, gmtoff_fraction = _strptime(data_string, format)
@@ -576,4 +576,16 @@ def _strptime_datetime(cls, data_string, format="%a %b %d %H:%M:%S %Y"):
             tz = datetime_timezone(tzdelta)
         args += (tz,)
 
-    return cls(*args)
+    dt = cls(*args)
+
+    if gmtoff is None and tzname is not None and infos:
+        try:
+            tz = infos[tzname]
+        except KeyError:
+            tz = None
+        except TypeError:
+            tz = infos(dt, tzname)
+        if tz:
+            dt = dt.replace(tzinfo=tz)
+
+    return dt
diff --git a/Lib/datetime.py b/Lib/datetime.py
@@ -1939,10 +1939,10 @@ def __str__(self):
         return self.isoformat(sep=' ')
 
     @classmethod
-    def strptime(cls, date_string, format):
+    def strptime(cls, date_string, format, tzinfos=None):
         'string, format -> new datetime parsed from a string (like time.strptime()).'
         import _strptime
-        return _strptime._strptime_datetime(cls, date_string, format)
+        return _strptime._strptime_datetime(cls, date_string, format, tzinfos)
 
     def utcoffset(self):
         """Return the timezone offset as timedelta positive east of UTC (negative west of

diff --git a/Misc/ACKS b/Misc/ACKS
@@ -1862,3 +1862,4 @@ Diego Rojas
 Edison Abahurire
 Geoff Shannon
 Batuhan Taskaya
+Arjan Keeman