-- Name: _date(text, text, text, text); Type: FUNCTION; Schema: py_functions; Owner: bien

CREATE FUNCTION _date(date text DEFAULT NULL::text, year text DEFAULT NULL::text, month text DEFAULT NULL::text, day text DEFAULT NULL::text) RETURNS text

import dateutil.tz

def e_str(e): return e.__class__.__name__+': '+e_msg(e)

def raise_invalid_value(cause, value):

    raise ValueError('invalid input value: "'+str(value)+'"\nDETAIL:  '

        +e_str(cause))

utc = dateutil.tz.tzutc()

def naive2utc(datetime_):

    assert datetime_.tzinfo == None

    return datetime_.replace(tzinfo=utc)

def from_timestamp(utc_timestamp):

    return naive2utc(datetime.datetime.utcfromtimestamp(utc_timestamp))

epoch = from_timestamp(0)

def strtotime(str_, default=epoch):

    import dateutil.parser

    return dateutil.parser.parse(str_, default=default)

if date != None:

    str_ = date

    try: year = float(str_)

    except ValueError:

        try: date = strtotime(str_)

        except ImportError: return str_

        except ValueError as e: raise_invalid_value(e, str_)

    else: date = (datetime.date(int(year), 1, 1) +

        datetime.timedelta(round((year % 1.)*365)))

else:

    # Year is required

    if year == None:

        if month == None and day == None: return None # entire date is empty

        else: raise AssertionError(

            'null value in column "year" violates not-null constraint')

    # Convert month name to number

    if month != None and not month.isdigit(): # month is name

        month = str(strtotime(month).month)

    if month == None: month = 1

    if day == None: day = 1

    year, month, day = map(int, (year, month, day))

    for try_num in range(2):

        try:

            date = datetime.date(year, month, day)

            break

        except ValueError as e:

            if try_num > 0: raise # exception still raised after retry

            msg = e_msg(e)

            if msg == 'month must be in 1..12': # try swapping month and day

                month, day = day, month

            else: raise

ALTER FUNCTION py_functions._date(date text, year text, month text, day text) OWNER TO bien;