Possible bug or documentation bug in TimeRecurrence() get_next() and get_prev() methods #224
Description
TimeRecurrence() get_next() and get_prev() Behaviour
The docstrings for the get_next() and get_prev() state the following.
"Return the next timepoint after this timepoint in the recurrence series, or None."
"Return the previous timepoint before this timepoint in the recurrence series, or None."
However, this only seems to work properly when providing a TimePoint that itself is a valid time in the recurrence series.
If you pass a TimePoint that isn't a valid TimePoint within the series, the methods will return the given TimePoint with the cycle duration added/subtracted, rather than returning None which I think should be the expected behaviour based on the docstrings.
import metomi.isodatetime.parsers as parse
recurrence = parse.TimeRecurrenceParser().parse('R/2000/P4Y')# Example where the given TimePoint does exist within the series.
date_time = parse.TimePointParser().parse('2000-01-01T00:00Z')
print(date_time)
print(recurrence.get_next(date_time))
print("Is this a valid TimePoint in this recurrence series?")
print(recurrence.get_is_valid(recurrence.get_next(date_time)))2000-01-01T00:00:00Z
2004-01-01T00:00:00Z
Is this a valid TimePoint in this recurrence series?
True
# Example where the given TimePoint does not exist in the series.
date_time = parse.TimePointParser().parse('2001-01-01T00:00Z')
print(date_time)
print(recurrence.get_next(date_time))
print("Is this a valid TimePoint in this recurrence series?")
print(recurrence.get_is_valid(recurrence.get_next(date_time)))2001-01-01T00:00:00Z
2005-01-01T00:00:00Z
Is this a valid TimePoint in this recurrence series?
False
# Example where the given TimePoint does not exist in the series.
date_time = parse.TimePointParser().parse('2007-01-01T00:00Z')
print(date_time)
print(recurrence.get_prev(date_time))
print("Is this a valid TimePoint in this recurrence series?")
print(recurrence.get_is_valid(recurrence.get_prev(date_time)))2007-01-01T00:00:00Z
2003-01-01T00:00:00Z
Is this a valid TimePoint in this recurrence series?
False
I think changing self.get_is_in_bounds() to self.get_is_valid in
isodatetime/metomi/isodatetime/data.py
Line 280 in 3216eb0
def get_next(self, timepoint: "TimePoint") -> "TimePoint":
"""Return the next timepoint after this timepoint in the recurrence
series, or None."""
if self._repetitions == 1 or timepoint is None:
return None
next_timepoint = timepoint + self._duration
if self._get_is_in_bounds(next_timepoint):
return next_timepoint
return None
def get_prev(self, timepoint: "TimePoint") -> "TimePoint":
"""Return the previous timepoint before this timepoint in the
recurrence series, or None."""
if self._repetitions == 1 or timepoint is None:
return None
prev_timepoint = timepoint - self._duration
if self._get_is_in_bounds(prev_timepoint):
return prev_timepoint
return None