Allow control over return type of parse_duration.

1 files changed, 10 insertions, 9 deletions

diff --git a/src/isodate/isoduration.py b/src/isodate/isoduration.py
index 88829f7..2de4981 100644
--- a/src/isodate/isoduration.py
+++ b/src/isodate/isoduration.py
@@ -51,10 +51,10 @@ ISO8601_PERIOD_REGEX = re.compile(
     r"((?P<separator>T)(?P<hours>[0-9]+([,.][0-9]+)?H)?"
     r"(?P<minutes>[0-9]+([,.][0-9]+)?M)?"
     r"(?P<seconds>[0-9]+([,.][0-9]+)?S)?)?$")
-# regular expression to parse ISO duartion strings.
+# regular expression to parse ISO duration strings.
 
 
-def parse_duration(datestring):
+def parse_duration(datestring, as_timedelta_if_possible: bool = True):
     """
     Parses an ISO 8601 durations into datetime.timedelta or Duration objects.
 
@@ -89,17 +89,18 @@ def parse_duration(datestring):
         # try alternative format:
         if datestring.startswith("P"):
             durdt = parse_datetime(datestring[1:])
-            if durdt.year != 0 or durdt.month != 0:
+            if as_timedelta_if_possible and durdt.year == 0 and durdt.month == 0:
+                # FIXME: currently not possible in alternative format
+                # create timedelta
+                ret = timedelta(days=durdt.day, seconds=durdt.second,
+                                microseconds=durdt.microsecond,
+                                minutes=durdt.minute, hours=durdt.hour)
+            else:
                 # create Duration
                 ret = Duration(days=durdt.day, seconds=durdt.second,
                                microseconds=durdt.microsecond,
                                minutes=durdt.minute, hours=durdt.hour,
                                months=durdt.month, years=durdt.year)
-            else:  # FIXME: currently not possible in alternative format
-                # create timedelta
-                ret = timedelta(days=durdt.day, seconds=durdt.second,
-                                microseconds=durdt.microsecond,
-                                minutes=durdt.minute, hours=durdt.hour)
             return ret
         raise ISO8601Error("Unable to parse duration string %r" % datestring)
     groups = match.groupdict()
@@ -114,7 +115,7 @@ def parse_duration(datestring):
                 # these values are passed into a timedelta object,
                 # which works with floats.
                 groups[key] = float(groups[key][:-1].replace(',', '.'))
-    if groups["years"] == 0 and groups["months"] == 0:
+    if as_timedelta_if_possible and groups["years"] == 0 and groups["months"] == 0:
         ret = timedelta(days=groups["days"], hours=groups["hours"],
                         minutes=groups["minutes"], seconds=groups["seconds"],
                         weeks=groups["weeks"])