# deltaTime.py # # Parser to convert a conversational time reference such as "in a minute" or # "noon tomorrow" and convert it to a Python datetime. The returned # ParseResults object contains # - original - the original time expression string # - computed_dt - the Python datetime representing the computed time # - relative_to - the reference "now" time # - time_offset - the difference between the reference time and the computed time # # BNF: # time_and_day ::= time_reference [day_reference] | day_reference 'at' absolute_time_of_day # day_reference ::= absolute_day_reference | relative_day_reference # absolute_day_reference ::= 'today' | 'tomorrow' | 'yesterday' | ('next' | 'last') weekday_name # relative_day_reference ::= 'in' qty day_units # | qty day_units 'ago' # | 'qty day_units ('from' | 'before' | 'after') absolute_day_reference # day_units ::= 'days' | 'weeks' # # time_reference ::= absolute_time_of_day | relative_time_reference # relative_time_reference ::= qty time_units ('from' | 'before' | 'after') absolute_time_of_day # | qty time_units 'ago' # | 'in' qty time_units # time_units ::= 'hours' | 'minutes' | 'seconds' # absolute_time_of_day ::= 'noon' | 'midnight' | 'now' | absolute_time # absolute_time ::= 24hour_time | hour ("o'clock" | ':' minute) ('AM'|'PM') # # qty ::= integer | integer_words | 'a couple of' | 'a' | 'the' # # Copyright 2010, 2019 by Paul McGuire # from datetime import datetime, time, timedelta import pyparsing as pp import calendar __all__ = ["time_expression"] # basic grammar definitions def make_integer_word_expr(int_name, int_value): return pp.CaselessKeyword(int_name).addParseAction(pp.replaceWith(int_value)) integer_word = pp.MatchFirst(make_integer_word_expr(int_str, int_value) for int_value, int_str in enumerate("one two three four five six seven eight nine ten" " eleven twelve thirteen fourteen fifteen sixteen" " seventeen eighteen nineteen twenty".split(), start=1)) integer = pp.pyparsing_common.integer | integer_word CK = pp.CaselessKeyword CL = pp.CaselessLiteral today, tomorrow, yesterday, noon, midnight, now = map(CK, "today tomorrow yesterday noon midnight now".split()) def plural(s): return CK(s) | CK(s + 's').addParseAction(pp.replaceWith(s)) week, day, hour, minute, second = map(plural, "week day hour minute second".split()) time_units = hour | minute | second any_time_units = week | day | time_units am = CL("am") pm = CL("pm") COLON = pp.Suppress(':') in_ = CK("in").setParseAction(pp.replaceWith(1)) from_ = CK("from").setParseAction(pp.replaceWith(1)) before = CK("before").setParseAction(pp.replaceWith(-1)) after = CK("after").setParseAction(pp.replaceWith(1)) ago = CK("ago").setParseAction(pp.replaceWith(-1)) next_ = CK("next").setParseAction(pp.replaceWith(1)) last_ = CK("last").setParseAction(pp.replaceWith(-1)) at_ = CK("at") on_ = CK("on") couple = (pp.Optional(CK("a")) + CK("couple") + pp.Optional(CK("of"))).setParseAction(pp.replaceWith(2)) a_qty = (CK("a") | CK("an")).setParseAction(pp.replaceWith(1)) the_qty = CK("the").setParseAction(pp.replaceWith(1)) qty = pp.ungroup(integer | couple | a_qty | the_qty).setName("qty") time_ref_present = pp.Empty().addParseAction(pp.replaceWith(True))('time_ref_present') def fill_24hr_time_fields(t): t['HH'] = t[0] t['MM'] = t[1] t['SS'] = 0 t['ampm'] = ('am','pm')[t.HH >= 12] def fill_default_time_fields(t): for fld in 'HH MM SS'.split(): if fld not in t: t[fld] = 0 weekday_name_list = list(calendar.day_name) weekday_name = pp.oneOf(weekday_name_list) _24hour_time = (~(integer + any_time_units) + pp.Word(pp.nums, exact=4).addParseAction(lambda t: [int(t[0][:2]),int(t[0][2:])], fill_24hr_time_fields) ) _24hour_time.setName("0000 time") ampm = am | pm timespec = (integer("HH") + pp.Optional(CK("o'clock") | COLON + integer("MM") + pp.Optional(COLON + integer("SS")) ) + (am | pm)("ampm") ).addParseAction(fill_default_time_fields) absolute_time = _24hour_time | timespec absolute_time_of_day = noon | midnight | now | absolute_time def add_computed_time(t): if t[0] in 'now noon midnight'.split(): t['computed_time'] = {'now': datetime.now().time().replace(microsecond=0), 'noon': time(hour=12), 'midnight': time()}[t[0]] else: t['HH'] = {'am': int(t['HH']) % 12, 'pm': int(t['HH']) % 12 + 12}[t.ampm] t['computed_time'] = time(hour=t.HH, minute=t.MM, second=t.SS) absolute_time_of_day.addParseAction(add_computed_time) # relative_time_reference ::= qty time_units ('from' | 'before' | 'after') absolute_time_of_day # | qty time_units 'ago' # | 'in' qty time_units time_units = hour | minute | second relative_time_reference = (qty('qty') + time_units('units') + ago('dir') | qty('qty') + time_units('units') + (from_ | before | after)('dir') + pp.Group(absolute_time_of_day)('ref_time') | in_('dir') + qty('qty') + time_units('units') ) def compute_relative_time(t): if 'ref_time' not in t: t['ref_time'] = datetime.now().time().replace(microsecond=0) else: t['ref_time'] = t.ref_time.computed_time delta_seconds = {'hour': 3600, 'minute': 60, 'second': 1}[t.units] * t.qty t['time_delta'] = timedelta(seconds=t.dir * delta_seconds) relative_time_reference.addParseAction(compute_relative_time) time_reference = absolute_time_of_day | relative_time_reference def add_default_time_ref_fields(t): if 'time_delta' not in t: t['time_delta'] = timedelta() time_reference.addParseAction(add_default_time_ref_fields) # absolute_day_reference ::= 'today' | 'tomorrow' | 'yesterday' | ('next' | 'last') weekday_name # day_units ::= 'days' | 'weeks' day_units = day | week weekday_reference = pp.Optional(next_ | last_, 1)('dir') + weekday_name('day_name') def convert_abs_day_reference_to_date(t): now = datetime.now().replace(microsecond=0) # handle day reference by weekday name if 'day_name' in t: todaynum = now.weekday() daynames = [n.lower() for n in weekday_name_list] nameddaynum = daynames.index(t.day_name.lower()) # compute difference in days - if current weekday name is referenced, then # computed 0 offset is changed to 7 if t.dir > 0: daydiff = (nameddaynum + 7 - todaynum) % 7 or 7 else: daydiff = -((todaynum + 7 - nameddaynum) % 7 or 7) t["abs_date"] = datetime(now.year, now.month, now.day) + timedelta(daydiff) else: name = t[0] t["abs_date"] = { "now" : now, "today" : datetime(now.year, now.month, now.day), "yesterday" : datetime(now.year, now.month, now.day) + timedelta(days=-1), "tomorrow" : datetime(now.year, now.month, now.day) + timedelta(days=+1), }[name] absolute_day_reference = today | tomorrow | yesterday | now + time_ref_present | weekday_reference absolute_day_reference.addParseAction(convert_abs_day_reference_to_date) # relative_day_reference ::= 'in' qty day_units # | qty day_units 'ago' # | 'qty day_units ('from' | 'before' | 'after') absolute_day_reference relative_day_reference = (in_('dir') + qty('qty') + day_units('units') | qty('qty') + day_units('units') + ago('dir') | qty('qty') + day_units('units') + (from_ | before | after)('dir') + absolute_day_reference('ref_day') ) def compute_relative_date(t): now = datetime.now().replace(microsecond=0) if 'ref_day' in t: t['computed_date'] = t.ref_day else: t['computed_date'] = now.date() day_diff = t.dir * t.qty * {'week': 7, 'day': 1}[t.units] t['date_delta'] = timedelta(days=day_diff) relative_day_reference.addParseAction(compute_relative_date) # combine expressions for absolute and relative day references day_reference = relative_day_reference | absolute_day_reference def add_default_date_fields(t): if 'date_delta' not in t: t['date_delta'] = timedelta() day_reference.addParseAction(add_default_date_fields) # combine date and time expressions into single overall parser time_and_day = (time_reference + time_ref_present + pp.Optional(pp.Optional(on_) + day_reference) | day_reference + pp.Optional(at_ + absolute_time_of_day + time_ref_present)) # parse actions for total time_and_day expression def save_original_string(s, l, t): # save original input string and reference time t['original'] = ' '.join(s.strip().split()) t['relative_to'] = datetime.now().replace(microsecond=0) def compute_timestamp(t): # accumulate values from parsed time and day subexpressions - fill in defaults for omitted parts now = datetime.now().replace(microsecond=0) if 'computed_time' not in t: t['computed_time'] = t.ref_time or now.time() if 'abs_date' not in t: t['abs_date'] = now # roll up all fields and apply any time or day deltas t['computed_dt'] = ( t.abs_date.replace(hour=t.computed_time.hour, minute=t.computed_time.minute, second=t.computed_time.second) + (t.time_delta or timedelta(0)) + (t.date_delta or timedelta(0)) ) # if time just given in terms of day expressions, zero out time fields if not t.time_ref_present: t['computed_dt'] = t.computed_dt.replace(hour=0, minute=0, second=0) # add results name compatible with previous version t['calculatedTime'] = t.computed_dt # add time_offset fields t['time_offset'] = t.computed_dt - t.relative_to def remove_temp_keys(t): # strip out keys that are just used internally all_keys = list(t.keys()) for k in all_keys: if k not in ('computed_dt', 'original', 'relative_to', 'time_offset', 'calculatedTime'): del t[k] time_and_day.addParseAction(save_original_string, compute_timestamp, remove_temp_keys) time_expression = time_and_day if __name__ == "__main__": current_time = datetime.now() # test grammar tests = """\ today tomorrow yesterday the day before yesterday the day after tomorrow 2 weeks after today in a couple of days a couple of days from now a couple of days from today in a day 3 days ago 3 days from now a day ago an hour ago in 2 weeks in 3 days at 5pm now 10 minutes ago 10 minutes from now in 10 minutes in a minute in a couple of minutes 20 seconds ago in 30 seconds in an hour in a couple hours in a couple days 20 seconds before noon ten seconds before noon tomorrow noon midnight noon tomorrow 6am tomorrow 0800 yesterday 1700 tomorrow 12:15 AM today 3pm 2 days from today a week from today a week from now three weeks ago noon next Sunday noon Sunday noon last Sunday 2pm next Sunday next Sunday at 2pm last Sunday at 2pm 10 seconds ago 100 seconds ago 1000 seconds ago 10000 seconds ago """ time_of_day = timedelta(hours=current_time.hour, minutes=current_time.minute, seconds=current_time.second) expected = { 'now' : timedelta(0), "10 seconds ago": timedelta(seconds=-10), "100 seconds ago": timedelta(seconds=-100), "1000 seconds ago": timedelta(seconds=-1000), "10000 seconds ago": timedelta(seconds=-10000), '10 minutes ago': timedelta(minutes=-10), '10 minutes from now': timedelta(minutes=10), 'in 10 minutes': timedelta(minutes=10), 'in a minute': timedelta(minutes=1), 'in a couple of minutes': timedelta(minutes=2), '20 seconds ago': timedelta(seconds=-20), 'in 30 seconds': timedelta(seconds=30), 'in an hour': timedelta(hours=1), 'in a couple hours': timedelta(hours=2), 'a week from now': timedelta(days=7), '3 days from now': timedelta(days=3), 'a couple of days from now': timedelta(days=2), 'an hour ago': timedelta(hours=-1), 'in a couple days': timedelta(days=2) - time_of_day, 'a week from today': timedelta(days=7) - time_of_day, 'three weeks ago': timedelta(days=-21) - time_of_day, 'a day ago': timedelta(days=-1) - time_of_day, 'in a couple of days': timedelta(days=2) - time_of_day, 'a couple of days from today': timedelta(days=2) - time_of_day, '2 weeks after today': timedelta(days=14) - time_of_day, 'in 2 weeks': timedelta(days=14) - time_of_day, 'the day after tomorrow': timedelta(days=2) - time_of_day, 'tomorrow': timedelta(days=1) - time_of_day, 'the day before yesterday': timedelta(days=-2) - time_of_day, 'yesterday': timedelta(days=-1) - time_of_day, 'today': -time_of_day, 'midnight': -time_of_day, 'in a day': timedelta(days=1) - time_of_day, '3 days ago': timedelta(days=-3) - time_of_day, 'noon tomorrow': timedelta(days=1) - time_of_day + timedelta(hours=12), '6am tomorrow': timedelta(days=1) - time_of_day + timedelta(hours=6), '0800 yesterday': timedelta(days=-1) - time_of_day + timedelta(hours=8), '1700 tomorrow': timedelta(days=1) - time_of_day + timedelta(hours=17), '12:15 AM today': -time_of_day + timedelta(minutes=15), '3pm 2 days from today': timedelta(days=2) - time_of_day + timedelta(hours=15), 'ten seconds before noon tomorrow': timedelta(days=1) - time_of_day + timedelta(hours=12) + timedelta(seconds=-10), '20 seconds before noon': -time_of_day + timedelta(hours=12) + timedelta(seconds=-20), 'in 3 days at 5pm': timedelta(days=3) - time_of_day + timedelta(hours=17), } def verify_offset(instring, parsed): time_epsilon = timedelta(seconds=1) if instring in expected: # allow up to a second time discrepancy due to test processing time if (parsed.time_offset - expected[instring]) <= time_epsilon: parsed['verify_offset'] = 'PASS' else: parsed['verify_offset'] = 'FAIL' print("(relative to %s)" % datetime.now()) time_expression.runTests(tests, postParse=verify_offset)