NAME

DateTime::Format::JP - Japanese DateTime Parser and Formatter

SYNOPSIS

use DateTime::Format::JP;
my $fmt = DateTime::Format::JP->new(
    hankaku      => 1,
    pattern      => '%c', # default
    traditional  => 0,
    kanji_number => 0,
    zenkaku      => 0,
    time_zone    => 'local',
);
my $dt = DateTime->now;
$dt->set_formatter( $fmt );
# set the encoding in and out to utf8
use open ':std' => ':utf8';
print "$dt\n"; # will print something like 令和3年7月12日午後2:30:20

my $dt  = $fmt->parse_datetime( "令和３年７月１２日午後２時３０分" );

my $str = $fmt->format_datetime( $dt );
print "$str\n";

VERSION

v0.1.5

DESCRIPTION

This module is used to parse and format Japanese date and time. It is lightweight and yet versatile.

It implements 2 main methods: "parse_datetime" and "format_datetime" both expect and return decoded utf8 string.

You can use Encode to decode and encode from perl internal utf8 representation to real utf8 and vice versa.

METHODS

new

The constructor accepts the following parameters:

hankaku boolean

If true, the digits used will be "half-size" (半角), or roman numbers like 1, 2, 3, etc.

The opposite is zenkaku (全角) or full-width. This will enable the use of double-byte Japanese numbers that still look like roman numbers, such as: １, ２, ３, etc.

Defaults to true.

pattern string

The pattern to use to format the date and time. See below the available "PATTERN TOKENS" and their meanings.

Defaults to %c

traditional boolean

If true, then it will use a more traditional date/time representation. The effect of this parameter on the formatting is documented in "PATTERN TOKENS"

kanji_number boolean

If true, this will have "format_datetime" use numbers in kanji, such as: 一, 二, 三, 四, etc.

zenkaku boolean

If true, this will use full-width, ie double-byte Japanese numbers that still look like roman numbers, such as: １, ２, ３, etc.

time_zone string

The time zone to use when creating a DateTime object. Defaults to local if DateTime::TimeZone supports it, otherwise it will fallback on UTC

error

Returns the latest error set, if any.

All method in this module return undef upon error and set an error that can be retrieved with this method.

format_datetime

Takes a DateTime object and returns a formatted date and time based on the pattern specified, which defaults to %c.

You can call this method directly, or you can set this formatter object in "set_formatter" in DateTime so that ie will be used for stringification of the DateTime object.

See below "PATTERN TOKENS" for the available tokens and their meanings.

hankaku

Sets or gets the boolean value for hankaku.

kanji_number

Sets or gets the boolean value for kanji_number.

parse_datetime

Takes a string representing a Japanese date, parse it and return a new DateTime. If an error occurred, it will return undef and you can get the error using "error"

time_zone

Sets or gets the string representing the time zone to use when creating DateTime object. This is used by "parse_datetime"

traditional

Sets or gets the boolean value for traditional.

zenkaku

Sets or gets the boolean value for zenkaku.

SUPPORT METHODS

kanji_to_romaji

Takes a number in kanji and returns its equivalent value in roman (regular) numbers.

lookup_era

Takes an Japanese era in kanji and returns an DateTime::Format::JP::Era object

lookup_era_by_date

Takes a DateTime object and returns a DateTime::Format::JP::Era object

make_datetime

Returns a DateTime based on parameters provided.

romaji_to_kanji

Takes a number and returns its equivalent representation in Japanese kanji. Thus, for example, 1234 would be returned as 千二百三十四

Please note that, since this is intended to be used only for dates, it does not format number over 9 thousand. If you think there is such need, please contact the author.

romaji_to_kanji_simple

Replaces numbers with their Japanese kanji equivalent. It does not use numerals.

romaji_to_zenkaku

Takes a number and returns its equivalent representation in double-byte Japanese numbers. Thus, for example, 1234 would be returned as １２３４

zenkaku_to_romaji

Takes a string representing a number in full width (全角), i.e. double-byte and returns a regular equivalent number. Thus, for example, １２３４ would be returned as 1234

PATTERN TOKENS

Here are below the available tokens for formatting and the value they represent.

In all respect, they are closely aligned with "strftime" in DateTime (see "strftime Patterns" in DateTime), except that the formatter object parameters provided upon instantiation alter the values used.

• %%

  The % character.

• %a

  The weekday name in abbreviated form such as: 月, 火, 水, 木, 金, 土, 日

• %A

  The weekday name in its long form such as: 月曜日, 火曜日, 水曜日, 木曜日, 金曜日, 土曜日, 日曜日

• %b

  The month name, such as 1月, 2月, etc... 12月 using regular digits.

• %B

  The month name using full width (全角) digits, such as １月, ２月, etc... １２月

• %h

  The month name using kanjis for numbers, such as 一月, 二月, etc... 十二月

• %c

  The datetime format in the Japanese standard most usual form. For example for 12th July 2021 14:17:30 this would be:

  令和3年7月12日午後2:17:30

  However, if traditional is true, then it would rather be:

  令和3年7月12日午後2時17分30秒

  And if zenkaku is true, it will use double-byte numbers instead:

  令和３年７月１２日午後２時１７分３０秒

  And if kanji_number is true, it will then be:

  令和三年七月十二日午後二時十七分三十秒

• %C

  The century number (year/100) as a 2-digit integer. This is the same as "strftime" in DateTime

• %d or %e

  The day of month (1-31).

  However, if zenkaku is true, then it would rather be with full width (全角) numbers: １-３１

  And if kanji_number is true, it will then be with numbers in kanji: 一, 二, etc.. 十, 十一, etc..

• %D

  Equivalent to %E%y年%m月%d日

  This is the Japanese style date including with the leading era name.

  If zenkaku is true, "full-width" (double byte) digits will be used and if kanji_number is true, numbers in kanji will be used instead.

  See %F for an equivalent date using the Gregorian years rather than the Japanese era.

• %E

  This extension is the Japanese era, such as 令和 (i.e. "reiwa": the current era)

• %F

  Equivalent to %Y年%m月%d日

  If zenkaku is true, "full-width" (double byte) digits will be used and if kanji_number is true, numbers in kanji will be used instead.

  For the year only the conversion from regular digits to Japanese kanjis will be done simply by interpolating the digits and not using numerals. For example 2021 would become 二〇二一 and not 二千二十一

• %g

  The year corresponding to the ISO week number, but without the century (0-99). This uses regular digits and is the same as "strftime" in DateTime

• %G

  The ISO 8601 year with century as a decimal number. The 4-digit year corresponding to the ISO week number. This has the same format and value as %Y, except that if the ISO week number belongs to the previous or next year, that year is used instead. Also this returns regular digits.

  This uses regular digits and is the same as "strftime" in DateTime

• %H

  The hour: 0-23

  If traditional is enabled, this would rather be 0-23時

  However, if zenkaku is true, then it would rather use full width (全角) numbers: ０-２３時

  And if kanji_number is true, it will then be something like 十時

• %I

  The hour on a 12-hour clock (1-12).

  If zenkaku is true, it will use full width numbers and if kanji_number is true, it will use numbers in kanji instead.

• %j

  The day number in the year (1-366). This uses regular digits and is the same as "strftime" in DateTime

• %m

  The month number (1-12).

  If zenkaku is true, it will use full width numbers and if kanji_number is true, it will use numbers in kanji instead.

• %M

  The minute: 0-59

  If traditional is enabled, this would rather be 0-59分

  However, if zenkaku is true, then it would rather use full width (全角) numbers: ０-５９分

  And if kanji_number is true, it will then be something like 十分

• %n

  Arbitrary whitespace. Same as in "strftime" in DateTime

• %N

  Nanoseconds. For other sub-second values use %[number]N.

  This is a pass-through directly to "strftime" in DateTime

• %p or %P

  Either produces the same result.

  Either AM (午前) or PM (午後) according to the given time value. Noon is treated as pm "午後" and midnight as am "午前".

• %r

  Equivalent to %p%I:%M:%S

  Note that if zenkaku is true, the semi-colon used will be double-byte: ：

  Also if you use this, do not enable kanji_number, because the result would be weird, something like:

  午後二：十四：三十 # 2:14:30 in this example

• %R

  Equivalent to %H:%M

  Note that if zenkaku is true, the semi-colon used will be double-byte: ：

  Juste like for %r, avoid enabling kanji_number if you use this token.

• %s

  Number of seconds since the Epoch.

  If zenkaku is enabled, this will return the value as double-byte number.

• %S

  The second: 0-60

  If traditional is enabled, this would rather be 0-60秒

  However, if zenkaku is true, then it would rather use full width (全角) numbers: ０-６０秒

  And if kanji_number is true, it will then be something like 六十秒

  (60 may occur for leap seconds. See DateTime::LeapSecond).

• %t

  Arbitrary whitespace. Same as in "strftime" in DateTime

• %T

  Equivalent to %H:%M:%S

  However, if zenkaku option is enabled, the numbers will be double-byte roman numbers and the separator will also be double-byte. For example:

  １４：２０：３０

• %U

  The week number with Sunday (日曜日) the first day of the week (0-53). The first Sunday of January is the first day of week 1.

  If zenkaku is enabled, it will return a double-byte number instead.

• %u

  The weekday number (1-7) with Monday (月曜日) = 1, 火曜日 = 2, 水曜日 = 3, 木曜日 = 4, 金曜日 = 5, 土曜日 = 6, 日曜日 = 7

  If zenkaku is enabled, it will return a double-byte number instead.

  This is the DateTime standard.

• %w

  The weekday number (0-6) with Sunday = 0.

  If zenkaku is enabled, it will return a double-byte number instead.

• %W

  The week number with Monday (月曜日) the first day of the week (0-53). The first Monday of January is the first day of week 1.

  If zenkaku is enabled, it will return a double-byte number instead.

• %x

  The date format in the standard most usual form. For example for 12th July 2021 this would be:

  令和3年7月12日

  However, if zenkaku is true, then it would rather be:

  令和３年７月１２日

  And if kanji_number is true, it will then be:

  令和三年七月十二日

• %X

  The time format in the standard most usual form. For example for 14:17:30 this would be:

  午後2:17:30

  And if zenkaku is enabled, it would rather use a double-byte numbers and separator:

  午後２：１７：３０

  However, if traditional is true, then it would rather be:

  午後2時17分30秒

  And if kanji_number is true, it will then be:

  午後二時十七分三十秒

• %y

  The year of the era. For example 2021-07-12 would be 令和3年7月12日 and thus the year value would be 3

  If zenkaku is true, it will use full width numbers and if kanji_number is true, it will use numbers in kanji instead.

• %Y

  A 4-digit year, including century (for example, 1991).

  If zenkaku is true, "full-width" (double byte) digits will be used and if kanji_number is true, numbers in kanji will be used instead.

  Same as in %F, the conversion from regular digits to Japanese kanjis will be done simply by interpolating the digits and not using numerals. For example 2021 would become 二〇二一 and not 二千二十一

• %z

  An RFC-822/ISO 8601 standard time zone specification. (For example +1100)

  If zenkaku is true, "full-width" (double byte) digits and +/- signs will be used and if kanji_number is true, numbers in kanji will be used instead. However, no numeral will be used. Thus a time zone offset such as +0900 would be returned as ＋〇九〇〇

• %Z

  The timezone name. (For example EST -- which is ambiguous). This is the same as "strftime" in DateTime

HISTORICAL NOTE

Japanese eras, also known as 元号 (gengo) or 年号 (nengo) form one of the two parts of a Japanese year in any given date.

It was instituted by and under first Emperor Kōtoku in 645 AD. So be warned that requiring an era-based Japanese date before will not yield good results.

Era name were adopted for various reasons such as a to commemorate an auspicious or ward off a malign event, and it is only recently that era name changes are tied to a new Emperor.

More on this here

From 1334 until 1392, there were 2 competing regimes in Japan; the North and South. This period was called "Nanboku-chō" (南北朝). This module uses the official Northern branch.

Also there has been two times during the period "Asuka" (飛鳥時代) with no era names, from 654/11/24 until 686/8/14 after Emperor Kōtoku death and from 686/10/1 until 701/5/3 after Emperor Tenmu's death just 2 months after his enthronement.

Thus if you want a Japanese date using era during those two periods, you will get and empty era.

More on this here

AUTHOR

Jacques Deguest <jack@deguest.jp>

SEE ALSO

DateTime

COPYRIGHT & LICENSE

Copyright(c) 2021 DEGUEST Pte. Ltd. DEGUEST Pte. Ltd.

You can use, copy, modify and redistribute this package and associated files under the same terms as Perl itself.

cpanm DateTime::Format::JP

perl -MCPAN -e shell
install DateTime::Format::JP