Use of TimePoint in parsing datetime-like duration format

[MetRonnie]

When using the datetime-like duration format, e.g. P0004-03-10 for P4Y3M10D, but without specifying the month or the day of month, it sets the month and day to 1

from metomi.isodatetime.parsers import DurationParser
parser = DurationParser()
print(parser.parse('P0004'))
# P4Y1M1D

This is because DurationParser.parse() parses the duration (without the P at the start) as a TimePoint, and TimePoint automatically sets the date to 1st Jan if the month & day are not specified

[MetRonnie]

Relevant LOC:

isodatetime/metomi/isodatetime/parsers.py

Lines 594 to 619 in a7c9d7d

	try:
	timepoint = parse_timepoint_expression(
	expression[1:],
	# this is a duration but we are parsing it as a timepoint
	# so don't validate.
	validate=False,
	allow_truncated=False,
	assumed_time_zone=(0, 0)
	)
	except ISO8601SyntaxError:
	raise ISO8601SyntaxError("duration", expression)
	if timepoint.get_is_week_date():
	raise ISO8601SyntaxError("duration", expression)
	result_map = {}
	result_map["years"] = timepoint.year
	if timepoint.get_is_calendar_date():
	result_map["months"] = timepoint.month_of_year
	result_map["days"] = timepoint.day_of_month
	if timepoint.get_is_ordinal_date():
	result_map["days"] = timepoint.day_of_year
	result_map["hours"] = timepoint.hour_of_day
	if timepoint.minute_of_hour is not None:
	result_map["minutes"] = timepoint.minute_of_hour
	if timepoint.second_of_minute is not None:
	result_map["seconds"] = timepoint.second_of_minute
	return data.Duration(**result_map)

isodatetime/metomi/isodatetime/parsers.py

Lines 623 to 626 in a7c9d7d

	def parse_timepoint_expression(timepoint_expression, validate=True, **kwargs):
	"""Return a data model that represents timepoint_expression."""
	parser = TimePointParser(**kwargs)
	return parser.parse(timepoint_expression, validate=validate)