# DateTime::Format::ISO8601 - phpMan

## NAME
    [DateTime::Format::ISO8601] - Parses ISO8601 formats

## VERSION
    version 0.16

## SYNOPSIS
        use [DateTime::Format::ISO8601];

        my $datetime_str = '2020-07-25T11:32:31';
        my $dt = [DateTime::Format::ISO8601]->parse_datetime($datetime_str);
        say $dt;

        # This format is ambiguous and could be either a date or time, so use the
        # parse_time method.
        my $time_str = '113231';
        $dt = [DateTime::Format::ISO8601]->parse_time($time_str);
        say $dt;

        # or

        my $iso8601 = [DateTime::Format::ISO8601]->new;
        $dt = $iso8601->parse_datetime($datetime_str);
        say $dt;

        $dt = $iso8601->parse_time($time_str);
        say $dt;

        say [DateTime::Format::ISO8601]->format_datetime($dt);

## DESCRIPTION
    Parses almost all ISO8601 date and time formats. ISO8601 time-intervals
    will be supported in a later release.

## METHODS
    This class provides the following methods:

  Constructors
   [DateTime::Format::ISO8601]->new( ... )
    Accepts an optional hash.

        my $iso8601 = [DateTime::Format::ISO8601]->new(
            base_datetime => $dt,
            cut_off_year  => 42,
            legacy_year   => 1,
        );

    *   base_datetime

        A "DateTime" object that will be used to fill in missing information
        from incomplete date/time formats.

        This key is optional.

    *   cut_off_year

        A integer representing the cut-off point between interpreting
        2-digits years as 19xx or 20xx.

            2-digit years <  cut_off_year will be interpreted as 20xx
            2-digit years >= cut_off_year will be untreated as 19xx

        This key defaults to the value of "DefaultCutOffYear".

    *   legacy_year

        A boolean value controlling if a 2-digit year is interpreted as
        being in the current century (unless a "base_datetime" is set) or if
        "cut_off_year" should be used to place the year in either 20xx or
        19xx.

        If this is true, then the "cut_off_year" is used. If this is false,
        then the year is always interpreted as being in the current century.

        This key defaults to the value of "DefaultLegacyYear".

   $iso8601->clone
    Returns a replica of the given object.

  Object Methods
   $iso8601->base_datetime
    Returns a "DateTime" object if a "base_datetime" has been set.

   $iso8601->set_base_datetime( object => $object )
    Accepts a "DateTime" object that will be used to fill in missing
    information from incomplete date/time formats.

   $iso8601->cut_off_year
    Returns a integer representing the cut-off point between interpreting
    2-digits years as 19xx or 20xx.

   $iso8601->set_cut_off_year($int)
    Accepts a integer representing the cut-off point between interpreting
    2-digits years as 19xx or 20xx.

        2-digit years <  legacy_year will be interpreted as 20xx
        2-digit years >= legacy_year will be interpreted as 19xx

   $iso8601->legacy_year
    Returns a boolean value indicating the 2-digit year handling behavior.

   $iso8601->set_legacy_year($bool)
    Accepts a boolean value controlling if a 2-digit year is interpreted as
    being in the current century (unless a "base_datetime" is set) or if
    "cut_off_year" should be used to place the year in either 20xx or 19xx.

  Class Methods
   [DateTime::Format::ISO8601]->DefaultCutOffYear($int)
    Accepts a integer representing the cut-off point for 2-digit years when
    calling "parse_*" as class methods and the default value for
    "cut_off_year" when creating objects. If called with no parameters this
    method will return the default value for "cut_off_year".

   [DateTime::Format::ISO8601]->DefaultLegacyYear($bool)
    Accepts a boolean value controlling the legacy year behavior when
    calling "parse_*" as class methods and the default value for
    "legacy_year" when creating objects. If called with no parameters this
    method will return the default value for "legacy_year".

  Parser(s)
    These methods may be called as either class or object methods.

   parse_datetime
   parse_time
    Please see the "FORMATS" section.

  Formatter
    This may be called as either class or object method.

   format_datetime($dt)
    Formats the datetime in an ISO8601-compatible format. This differs from
    "iso8601" in DateTime by including nanoseconds/milliseconds and the
    correct timezone offset.

## FORMATS
    There are 6 strings that can match against date only or time only
    formats. The "parse_datetime" method will attempt to match these
    ambiguous strings against date only formats. If you want to match
    against the time only formats use the "parse_time" method.

  Conventions
    *   Expanded ISO8601

        These formats are supported with exactly 6 digits for the year.
        Support for a variable number of digits will be in a later release.

    *   Precision

        If a format doesn't include a year all larger time unit up to and
        including the year are filled in using the current date/time or [if
        set] the "base_datetime" object.

    *   Fractional time

        There is no limit on the expressed precision.

  Supported via parse_datetime
    The supported formats are listed by the section of ISO 8601:2000(E) in
    which they appear.

   5.2 Dates
    *   5.2.1.1

        YYYYMMDD
        YYYY-MM-DD

    *   5.2.1.2

        YYYY-MM
        YYYY
        YY

    *   5.2.1.3

        YYMMDD
        YY-MM-DD
        -YYMM
        -YY-MM
        -YY
        --MMDD
        --MM-DD
        --MM
        ---DD

    *   5.2.1.4

        +[YY]YYYYMMDD
        +[YY]YYYY-MM-DD
        +[YY]YYYY-MM
        +[YY]YYYY
        +[YY]YY

    *   5.2.2.1

        YYYYDDD
        YYYY-DDD

    *   5.2.2.2

        YYDDD
        YY-DDD
        -DDD

    *   5.2.2.3

        +[YY]YYYYDDD
        +[YY]YYYY-DDD

    *   5.2.3.1

        YYYYWwwD
        YYYY-Www-D

    *   5.2.3.2

        YYYYWww
        YYYY-Www
        YYWwwD
        YY-Www-D
        YYWww
        YY-Www
        -YWwwD
        -Y-Www-D
        -YWww
        -Y-Www
        -WwwD
        -Www-D
        -Www
        -W-D

    *   5.2.3.4

        +[YY]YYYYWwwD
        +[YY]YYYY-Www-D
        +[YY]YYYYWww
        +[YY]YYYY-Www

   5.3 Time of Day
    *   5.3.1.1 - 5.3.1.3

        Values can optionally be prefixed with 'T'.

    *   5.3.1.1

        hh:mm:ss

    *   5.3.1.2

        hh:mm

    *   5.3.1.3 - 5.3.1.4

        fractional (decimal) separator maybe either ',' or '.'

    *   5.3.1.3

        hhmmss,ss
        hh:mm:ss,ss
        hhmm,mm
        hh:mm,mm
        hh,hh

    *   5.3.1.4

        -mm:ss
        -mmss,s
        -mm:ss,s
        -mm,m
        --ss,s

    *   5.3.3 - 5.3.4.2

        Values can optionally be prefixed with 'T'.

    *   5.3.3

        hhmmssZ
        hh:mm:ssZ
        hhmmZ
        hh:mmZ
        hhZ
        hhmmss.ssZ
        hh:mm:ss.ssZ

    *   5.3.4.2

        hhmmss[+-]hhmm
        hh:mm:ss[+-]hh:mm
        hhmmss[+-]hh
        hh:mm:ss[+-]hh
        hhmmss.ss[+-]hhmm
        hh:mm:ss.ss[+-]hh:mm

   5.4 Combinations of date and time of day
    *   5.4.1

        YYYYMMDDThhmmss
        YYYY-MM-DDThh:mm:ss
        YYYYMMDDThhmmssZ
        YYYY-MM-DDThh:mm:ssZ
        YYYYMMDDThhmmss[+-]hhmm
        YYYY-MM-DDThh:mm:ss[+-]hh:mm
        YYYYMMDDThhmmss[+-]hh
        YYYY-MM-DDThh:mm:ss[+-]hh

    *   5.4.2

        YYYYMMDDThhmmss.ss
        YYYY-MM-DDThh:mm:ss.ss
        YYYYMMDDThhmmss.ss[+-]hh
        YYYY-MM-DDThh:mm:ss.ss[+-]hh
        YYYYMMDDThhmmss.ss[+-]hhmm
        YYYY-MM-DDThh:mm:ss.ss[+-]hh:mm

    *   5.4.3

        Support for this section is not complete.

        YYYYMMDDThhmm
        YYYY-MM-DDThh:mm
        YYYYMMDDThhmmZ
        YYYY-MM-DDThh:mmZ
        YYYYDDDThhmm
        YYYY-DDDThh:mm
        YYYYDDDThhmmZ
        YYYY-DDDThh:mmZ
        YYYYWwwDThhmm[+-]hhmm
        YYYY-Www-DThh:mm[+-]hh

   5.5 Time-Intervals
    These are not currently supported

  Supported via parse_time
   5.3.1.1 - 5.3.1.3
    Values can optionally be prefixed with 'T'.

    *   5.3.1.1

        hhmmss

    *   5.3.1.2

        hhmm
        hh

    *   5.3.1.4

        -mmss
        -mm
        --ss

## STANDARDS DOCUMENT
  Title
        ISO8601:2000(E)
        Data elements and interchange formats - information exchange -
        Representation of dates and times
        Second edition 2000-12-15

  Reference Number
        ISO/TC 154 N 362

## CREDITS
    Iain 'Spoon' Truskett (SPOON) who wrote [DateTime::Format::Builder]. That
    has grown into *The Vacuum Energy Powered "Swiss Army" Katana* of date
    and time parsing. This module was inspired by and conceived in honor of
    Iain's work.

    Tom Phoenix (PHOENIX) and PDX.pm for helping me solve the ISO week
    conversion bug. Not by fixing the code but motivation me to fix it so I
    could participate in a game of "Zendo".

    Jonathan Leffler (JOHNL) for reporting a test bug.

    Kelly McCauley for a patch to add 8 missing formats.

    Alasdair Allan (AALLAN) for complaining about excessive test execution
    time.

    Everyone at the DateTime "Asylum".

## SEE ALSO
    *   DateTime

    *   [DateTime::Format::Builder]

## SUPPORT
    Bugs may be submitted at
    <<https://github.com/houseabsolute/DateTime-Format-ISO8601/issues>>.

    I am also usually active on IRC as 'autarch' on "irc://irc.perl.org".

## SOURCE
    The source code repository for DateTime-Format-ISO8601 can be found at
    <<https://github.com/houseabsolute/DateTime-Format-ISO8601>>.

## AUTHORS
    *   Joshua Hoblitt <<josh@hoblitt.com>>

    *   Dave Rolsky <<autarch@urth.org>>

## CONTRIBUTORS
    *   Doug Bell <<doug@preaction.me>>

    *   joe <<draxil@gmail.com>>

    *   Liam Widdowson <<lbw@telstra.com>>

    *   Thomas Klausner <<domm@plix.at>>

## COPYRIGHT AND LICENSE
    This software is copyright (c) 2021 by Joshua Hoblitt.

    This is free software; you can redistribute it and/or modify it under
    the same terms as the Perl 5 programming language system itself.

    The full text of the license can be found in the LICENSE file included
    with this distribution.

