Badger::Date(3p)

NAME
Badger::Date - simple object representation of a date

SYNOPSIS
    use Badger::Date;

    # date defaults to today to date/time now
    my $date = Badger::Date->new();
    my $date = Badger::Date->today();

    # or from ISO-8601 date (or similar)
    my $stamp = Badger::Date->new('2015-03-19');

    # or from individual arguments
    my $date = Badger::Date->new(
        year    => 2015,
        month   => 3,
        day     => 19
    );

DESCRIPTION
This module implements a small and simple object for representing a date. Its scope is intentionally limited to the kind of applications that require very basic date functionality with minimal overhead.

For any non-trivial date manipulation you should almost certainly be using the most excellent DateTime modules instead.

This code is derived from Badger::Timestamp.

EXPORTABLE SUBROUTINES

  DATE
This is a shortcut aliases to "Badger::Date".

    use Badger::Date 'DATE';

    my $date = DATE->new();         # same as Badger::Date->new();

  Date()
This subroutine returns the name of the "Badger::Date" class when called without arguments. Thus it can be used as an alias for "Badger::Date" as per DATE.

    use Badger::Date 'Date';

    my $ts = Date->new();  # same as Badger::Date->new();

When called with arguments, it creates a new "Badger::Date" object.

    my $ts = Date($date);  # same as Badger::Date->new($date);

  Today()
Returns a "Badger::Date" for the current date.

METHODS

  new('YYYY-MM-DD')
Constructor method to create a new "Badger::Date" object from a date string or seconds since the epoch.

The date should contain 4 digits for the year and two for each of the month and day separated by any non-numerical characters.

    # examples of valid formats
    my $date = Badger::Date->new('2015-03-19');
    my $date = Badger::Date->new('2015/03/19');

The "Badger::Date" module converts these to the canonical form of "YYYY-MM-DD"

    my $date = Badger::Date->new('2015/03/19');
    print $date;       # 2015-03-19

You can also construct a "Badger::Date" object by specifying the number of seconds since the epoch. This is the value return by system functions like time() and used for file creation/modification times.

    my $stamp = Badger::Date->new(time());

Or can can pass it an existing "Badger::Date" object.

    my $stamp2 = Badger::Date->new($stamp);

If you don't specify any argument then you get the current system time as returned by time().

    my $now = Badger::Date->new;

  today()
Returns a "Badger::Date" object representing the current date.

  copy()
Returns a new "Badger::Date" object creates as a copy of the current one.

    my $copy = $date->copy;

This can be useful for making adjustments to a date without affecting the original object.

    my $later = $date->copy->adjust( months => 3 );

  date()
Returns the complete date in canonical form.

    print $date->date();  # 2015-03-19

This method is called automatically whenever the object is used as a string value.

    print $date;               # 2015-03-19

  format($format)
Returns a formatted version of the timestamp, generated using the POSIX strftime function.

    print $date->format('%d-%b-%y');

  year() / years()
Returns the year.

    print $date->year();       # 2015

Can also be called with an argument to change the year.

    $date->year(2016);

  month() / months()
Returns the month.

    print $date->month();      # 03

Can also be called with an argument to change the yonth.

    $date->month(04);

  day() / days()
Returns the day.

    print $date->day();        # 19

Can also be called with an argument to change the day.

    $date->day(20);

  days_in_month()
Returns the number of days in the current month. Accounts correctly for leap years.

  leap_year()
Returns a true value (1) if the year is a leap year, a false value (0) if not.

  epoch_time()
Returns the timestamp object as the number of seconds since the epoch time.

  compare($when)
This method is used to chronologically compare two dates to determine if one is earlier, later, or exactly equal to another.

The method can be passed another "Badger::Date" object to compare against or an argument or arguments from which a "Badger::Date" object can be constructed. If no arguments are passed then it defaults to a comparison against the current time.

    my $date    = Badger::Date->new('2015-01-10');
    my $compare = Badger::Date->new('2015-03-19');

    $date->before($compare);           # date object
    $date->before('2015-03-19');       # literal date
    $date->before($epoch_seconds);     # epoch seconds, e.g. from file time
    $date->before;                     # before now

The method returns -1 if the date object represents a date before the date passed as an argument, 1 if it's after, or 0 if it's equal.

  equal($when)
This is a method of convenience which uses compare() to test if two timestamps are equal. You can pass it any of the arguments accepted by the compare() method.

    if ($date1->equal($date2)) {
        print "both dates are equal\n";
    }

This method is overloaded onto the "==" operator, allowing you to perform more natural comparisons.

    if ($date1 == $date2) {
        print "both date are equal\n";
    }

  before($when)
This is a method of convenience which uses compare() to test if one date occurs before another. It returns a true value (1) if the first timestamp (the object) is before the second (the argument), or a false value (0) otherwise.

    if ($date1->before($date2)) {
        print "$date1 is before $date2\n";
    }

This method is overloaded onto the "<" operator.

    if ($date1 < $date2) {
        print "$date1 is before $date2\n";
    }

  after($when)
This is a method of convenience which uses compare() to test if one date occurs after another. It returns a true value (1) if the first date (the object) is after the second (the argument), or a false value (0) otherwise.

    if ($date1->after($date2)) {
        print "$date1 is after $date2\n";
    }

This method is overloaded onto the ">" operator.

    if ($date1 > $date2) {
        print "$date1 is after $date2\n";
    }

  not_equal($when)
This is an alias to the compare() method. It returns a true value (-1 or +1, both of which Perl considers to be true values) if the dates are not equal or false value (0) if they are.

    if ($date1->not_equal($date2)) {
        print "$date1 is not equal to $date2\n";
    }

This method is overloaded onto the "!=" operator.

    if ($date1 != $date2) {
        print "$date1 is not equal to $date2\n";
    }

  not_before($when)
This is a method of convenience which uses compare() to test if one date does not occur before another. It returns a true value (1) if the first date (the object) is equal to or after the second (the argument), or a false value (0) otherwise.

    if ($date1->not_before($date2)) {
        print "$date1 is not before $date2\n";
    }

This method is overloaded onto the ">=" operator.

    if ($date1 >= $date2) {
        print "$date1 is not before $date2\n";
    }

  not_after($when)
This is a method of convenience which uses compare() to test if one date does not occur after another. It returns a true value (1) if the first date (the object) is equal to or before the second (the argument), or a false value (0) otherwise.

    if ($date1->not_after($date2)) {
        print "$date1 is not after $date2\n";
    }

This method is overloaded onto the "<=" operator.

    if ($date1 <= $date2) {
        print "$date1 is not after $date2\n";
    }

  adjust(%adjustments)
Method to adjust the date by a fixed amount or amounts.

    # positive adjustment
    $date->adjust( months => 6, years => 1 );

    # negative adjustment
    $date->adjust( months => -18 );

Named parameters can be passed as arguments or via a hash reference.

    $date->adjust(  months => -18  );        # naked
    $date->adjust({ months => -18 });        # clothed

You can specify units using singular (day, month, year) or plural (days, months, years) keys. The method will correctly handle values outside the usual ranges. For example, you can specify a change of 18 months, -2000 days, and so on.

A single non-reference argument is assumed to be a duration which is converted to a number of seconds via the duration() method.

  duration($duration)
Returns the number of seconds in a duration. A single numerical argument is assumed to be a number of seconds and is returned unchanged.

    $date->adjust(300);     # 300 seconds

A single non-numerical argument should have a suffix indicating the units. In "compact form" this is a single letter. We use lower case "m" for minutes and upper case "M" for months.

    $date->adjust("2d");    # or "2 days"
    $date->adjust("6M");    # or "6 months"
    $date->adjust("5y");    # or "5 years"

Alternately you can spell the units out in full as shown in the right column above. However, we only look at the first character of the following word so you can write all sorts of nonsense which we will dutifully accept without complaint.

    $date->adjust("5 Monkeys"); # 5 months
    $date->adjust("9 doobies"); # 9 days
    $date->adjust("3 yaks");    # 3 years

For the sake of convenience, the method will automatically convert the word "month" into "Month" so that the first letter is correctly capitalised.

AUTHOR
Andy Wardley <http://wardley.org>

COPYRIGHT
Copyright (C) 2001-2015 Andy Wardley. All Rights Reserved.

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