/ 
Date-RangeParser-EN-0.04
River stage zero No dependents
/ Date::RangeParser::EN

NAME

Date::RangeParser::EN - Parser for plain English date/time range strings

SYNOPSIS

use Date::RangeParser::EN;

my $parser = Date::RangeParser::EN->new;
my ($begin, $end) = $parser->parse_range("this week");

DESCRIPTION

Parses plain-English strings representing date/time ranges

METHODS

new

Returns a new instance of Date::RangeParser::EN.

Takes an optional hash of parameters:

  • datetime_class

    By default, Date::RangeParser::EN returns two DateTime objects representing the beginning and end of the range. If you use a subclass of DateTime (or another module that implements the DateTime API), you may pass the name of this class to use it instead.

    At the very least, this given class must implement a new method that accepts a hash of arguments, where the following keys will be set:

    year
month
day
hour
minute
second

    This gives you the freedom to set your time zones and such however you need to.

  • now_callback

    By default, Date::RangeParser::EN uses DateTime->now to determine the current date/time for calculations. If you need to work with a different time (for instance, if you need to adjust for time zones), you may pass a callback (code reference) which returns a DateTime object.

parse_range

Accepts a string representing a plain-English date range, for instance:

  • today

  • this week

  • the past 2 months

  • next Tuesday

  • two weeks ago

  • the next 3 hours

  • the 3rd of next month

  • the end of this month

More formally, this will parse the following kinds of date strings:

NUMBER : ordinary number (1)
PERIOD : one of: hour, day, week, month, quarter, or year (or the plural of these)
WEEKDAY : one of: Monday, Tuesday, Wedensday, Thursday, Friday, Saturday, or Sunday
CARDINAL : a cardinal number (21st) or the word for that number (twenty-first) or end
MONTH : a month name: January, Feburary, March, April, May, June, July August, 
        September, October, November, or Decmeber or any 3-letter abbreviation
YEAR : a 4-digit year (2-digits will not work)
RANGE : any date range that can be parsed by parse_range

today                             : today, midnight to midnight

this PERIOD                       : the current period, start to end
this month

current PERIOD                    : the current period, start to end
current year

this WEEKDAY                      : the WEEKDAY that is in the current week, midnight to midnight
this Monday

NUMBER PERIOD ago                 : past date relative to now until now
3 days ago

past NUMBER PERIOD                : past date relative to now until now
past 2 weeks

last NUMBER PERIOD                : past date relative to now until now
last 6 hours

past NUMBER WEEKDAY               : the weekday a number of weeks before now until now
past 4 Saturdays

NUMBER WEEKDAY ago                : the weekday a number of weeks before now until now
3 Fridays ago

yesterday                         : yesterday, midnight to midnight

last WEEKDAY                      : the WEEKDAY that is in the week prior to this, midnight to midnight
last Wednesday

previous WEEKDAY                  : the WEEKDAY that is in the week prior to this, midnight to midnight
previous Friday

past WEEKDAY                      : the WEEKDAY that is in the week prior to this, midnight to midnight
past Tuesday

this past WEEKDAY                 : the WEEKDAY that is in the week prior to this, midnight to midnight
this past Saturday

coming WEEKDAY                    : the WEEKDAY that is in the week after this, midnight to midnight
coming Monday

this coming WEEKDAY               : the WEEKDAY that is in the week after this, midnight to midnight
this coming Thursday

NUMBER PERIOD hence               : now to a future date relative to now
4 months hence

NUMBER PERIOD from now            : now to a future date relative to now
6 days from now

next NUMBER PERIOD                : now to a future date relative to now
next 7 years

tomorrow                          : tomorrow, midnight to midnight

next NUMBER WEEKDAY               : the WEEKDAY that is in a number of weeks after this, midnight to midnight
next 4 Sundays

CARDINAL of this month            : the specified day of the current month, midnight to midnight
14th of this month

CARDINAL of last month            : the specified day of the previous month, midnight to midnight
31st of last month

CARDINAL of next month            : the specified day of the month following this, midnight to midnight
3rd of next month

CARDINAL of NUMBER months ago     : the specified day of a previous month, midnight to midnight
12th of 2 months ago

CARDINAL of NUMBER months from now : the specified day of a following month, midnight to midnight
7th of 22 months from now

CARDINAL of NUMBER months hence   : the specified day of a following month, midnight to midnight
22nd of 6 months hence

MONTH                             : the named month of the current year, 1st to last day
August

this MONTH                        : the named month of the current year, 1st to last day
this Sep

last MONTH                        : the named month of the previous year, 1st to last day
last January

next MONTH                        : the named month of the next year, 1st to last day
next Dec

MONTH YEAR                        : the named month of the named year, 1st to last day
June 1969

RANGE to RANGE                    : the very start of the first range to the very end of the second
Tuesday to Next Saturday

RANGE thru RANGE                  : the very start of the first range to the very end of the second
2 hours ago thru the next 6 hours

RANGE through RANGE               : the very start of the first range to the very end of the second
August through December

RANGE - RANGE                     : the very start of the first range to the very end of the second
9-1-2012 - 9-30-2012

RANGE-RANGE                       : the very start of the first range to the very end of the second
10/10-10/20                         (ranges must not contain hyphens, "-")

Anything else is parsed by Date::Manip. If Date::Manip is unable to parse the date given either, then the dates returned will be undefined.

Also, when parsing:

  • The word "the" will always be ignored and can appear anywhere.

  • Cardinal numbers may be spelled out as words, i.e. "September first" instead of "September 1st".

  • Any plural or singular period shown above can be used with the opposite.

  • All dates are parsed relative to the parser's notion of now. You can control this by setting the now_callback option on the constructor.

Returns two DateTime objects, reprensenting the beginning and end of the range.

TO DO

There's a lot more that this module could handle. A few items that come to mind:

  • More testing to make sure certain date configurations are handled, like start of week.

  • Handle Unicode in places where such handling makes sense (like hyphen detection)

  • Allow full words instead of digits ("two weeks ago" vs "2 weeks ago")

  • Allow "between" for ranges ("between last February and this Friday") in addition to "to/through" ranges

  • This module is US English-centric (hence the "EN") and might do some things wrong for other variants of English and a generic Date::RangeParser interface could be made to allow for other languages to be parsed this way.

  • Depends on Date::Manip. This may or may not be a good thing.

DEPENDENCIES

DateTime, Date::Manip

AUTHORS

This module was authored by Grant Street Group (http://grantstreet.com), which was kind enough to give it back to the Perl community.

The CPAN distribution is maintained by Michael Aquilina (aquilina@cpan.org).

COPYRIGHT AND LICENSE

Copyright (C) 2012 Grant Street Group.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.