/ 
Locale-Intl-v0.1.0
River stage one • 1 direct dependent • 1 total dependent
/ Locale::Intl

NAME

Locale::Intl - A Web Intl.Locale Class Implementation

SYNOPSIS

use Locale::Intl;
my $locale = Locale::Intl->new( 'ja-Kana-t-it' ) ||
    die( Locale::Intl->error );

my $korean = new Locale::Intl('ko', {
    script => 'Kore',
    region => 'KR',
    hourCycle => 'h23',
    calendar => 'gregory',
});

my $japanese = new Locale::Intl('ja-Jpan-JP-u-ca-japanese-hc-h12');

say $korean->baseName;
say $japanese->baseName;
# Expected output:
# ko-Kore-KR
# ja-Jpan-JP

say $korean->hourCycle;
say $japanese->hourCycle;
# Expected output
# h23
# h12

VERSION

v0.1.0

DESCRIPTION

This class inherits from Unicode::Locale.

Make sure to check the API of Unicode::Locale for its constructor and its methods.

It also accesses the Unicode CLDR (Common Locale Data Repository) data using Locale::Unicode::Data

It requires perl v5.10.1 minimum to run.

CONSTRUCTOR

# American English
my $us = Locale::Intl->new( 'en-US' );
# Japanese Katakana
my $ja = Locale::Intl->new( 'ja-Kana' );
# Swiss German as spoken in subdivision of Zurich
my $ch = Locale::Intl->new( 'gsw-u-sd-chzh' );
# Hebrew as spoken in Israel with Hebrew calendar and Jerusalem time zone
my $he = Locale::Intl->new( 'he-IL-u-ca-hebrew-tz-jeruslm' );
# Japanese with Japanese calendar and Tokyo time zone with Japanese Finance numbering
# translated from Austrian German by an unidentified vendor with private extension 'private-subtag'
my $ja = Locale::Intl->new( 'ja-t-de-AT-t0-und-u-ca-japanese-tz-jptyo-nu-jpanfin-x-private-subtag' );

Passing some overriding options:

my $locale = new Locale::Intl( 'en-US', { hourCycle => 'h12' });
say $locale->hourCycle; # h12

new

This takes a Unicode locale identifier and an optional hash or hash reference of options, and returns a new instance of Locale::Intl. For the syntax of locale identifier strings, see the Unicode documentation.

A locale is composed of a language, such as fr (French) or ja (Japanese) or gsw (Swiss German), an optional script, such as Latn (Latin) or Kana (Katanaka), a region, which can be a country code, such as US (United States) or a world region, such as 150 (Europe) and a variant, such as valencia as in ca-ES-valencia. Only the language part is required.

The supported options are:

METHODS

getAllCalendars

This is a read-only method that returns an array of all possible calendar values supported by the current version of LDML (Locale Data Markup Language).

getAllNumberingSystems

This is a read-only method that returns an array of all possible numbering system values supported by the current version of LDML (Locale Data Markup Language).

getAllTimeZones

This is a read-only method that returns an array of all possible time zone values supported by the current version of LDML (Locale Data Markup Language). Please note that to ensure consistency, the LDML supports some values that are either outdated or removed from IANA's time zone database.

getCalendars

my $jaJP = new Locale::Intl( 'ja-JP' );
say $jaJP->getCalendars(); # ["gregory", "japanese"]

This method returns an array of one or more unique calendar identifiers for this locale.

See the Unicode Locale BCP47 extensions for the list of valid calendar values.

getCollations

my $locale = Locale::Intl->new( 'zh' );
say $locale->getCollations(); # ["pinyin", "stroke", "zhuyin", "emoji", "eor"]

The getCollations() method returns an array of one or more collation types commonly used for this locale. If the Locale already has a collation, then the returned array contains that single value.

If the locale identifier object does not have a collation already, getCollations() lists all commonly-used collation types for the given locale identifier.

See the Unicode Locale BCP47 extensions for the list of valid collation values.

getHourCycles

my $jaJP = Locale::Intl->new( 'ja-JP' );
say $jaJP->getHourCycles(); # ["h23"]

my $arEG = Locale::Intl->new( 'ar-EG' );
say $arEG->getHourCycles(); # ["h12"]

This method returns an array of one or more unique hour cycle identifiers commonly used for this locale, sorted in descending preference. If the Locale already has an hourCycle, then the returned array contains that single value.

If the locale identifier object does not have a hourCycle already, this method lists all commonly-used hour cycle identifiers for the given locale.

Below are the valid values:

  • h12

    Hour system using 1–12; corresponds to h in patterns. The 12 hour clock, with midnight starting at 12:00 am. As used, for example, in the United States.

  • h23

    Hour system using 0–23; corresponds to H in patterns. The 24 hour clock, with midnight starting at 0:00.

  • h11

    Hour system using 0–11; corresponds to K in patterns. The 12 hour clock, with midnight starting at 0:00 am. Mostly used in Japan.

  • h24

    Hour system using 1–24; corresponds to k in pattern. The 24 hour clock, with midnight starting at 24:00. Not used anywhere.

Hour cycles usage in the world are:

  • h12 h23

    115 locales

  • h23 h12

    95 locales

  • h23

    60 locales

  • h23 h11 h12

    1 locale

See also the property hourCycle

getNumberingSystems

my $ja = Locale::Intl->new( 'ja' );
say $ja->getNumberingSystems(); # ["latn"]

my $arEG = Locale::Intl->new( 'ar-EG' );
say $arEG->getNumberingSystems(); # ["arab"]

This method returns an array of one or more unique numbering system identifiers commonly used for this locale, sorted in descending preference. If the Locale already has a numberingSystem, then the returned array contains that single value.

See the Unicode Locale BCP47 extensions for the list of valid numbering system values.

getTextInfo

my $ar = Locale::Intl->new( 'ar' );
say $ar->getTextInfo(); # rtl

my $es = Locale::Intl->new( 'es' );
say $es->getTextInfo(); # ltr

This method returns a string representing the ordering of characters indicated by either ltr (left-to-right) or by rtl (right-to-left) for this locale as specified in UTS 35 Layouts Elements.

getTimeZones

my $jaJP = Locale::Intl->new( 'ja-JP' );
say $jaJP->getTimeZones(); # ["Asia/Tokyo"]

my $ar = Locale::Intl->new( 'ar' );
# This will resolve to Africa/Cairo, because the locale 'ar' 
3 will maximize to ar-Arab-EG and from there to Egypt
say $ar->getTimeZones(); # ["Africa/Cairo"]

This method returns an array of supported time zones for this locale.

ach value is an IANA time zone canonical name, sorted in alphabetical order. If the locale identifier does not contain a region subtag, the returned value is undef.

Keep in mind that the values do not necessarily match the IANA database that changes from time to time. The Unicode LDML keeps old time zones for stability purpose.

Also note that this method behaves slightly differently from its JavaScript counter part, as the JavaScript getTimeZones() method will return undef if only a language subtag is provided and not a locale tha would include a country code. This method, instead, will maximize the 2-letters locale provided and from there will returns the time zone for the default country for that language.

See also getAllTimeZones to get a list of all available time zones.

getWeekInfo

const he = Locale::Intl->new( 'he' );
 say $he->getWeekInfo();
 # { firstDay => 7, weekend => [5, 6], minimalDays => 1 }

const af = Locale::Intl->new( 'af' );
say $af->getWeekInfo();
# { firstDay => 7, weekend => [6, 7], minimalDays => 1 }

const enGB = Locale::Intl->new( 'en-GB' );
say $enGB->getWeekInfo();
# { firstDay => 1, weekend => [6, 7], minimalDays => 4 }

const msBN = Locale::Intl->new( 'ms-BN' );
say $msBN->getWeekInfo();
# { firstDay => 7, weekend => [5, 7], minimalDays => 1 }
# Brunei weekend is Friday and Sunday but not Saturday

This method returns an hash reference with the properties firstDay, weekend and minimalDays for this locale, as specified in UTS 35 Week Elements.

  • firstDay

    An integer indicating the first day of the week for the locale. Can be either 1 (Monday) or 7 (Sunday).

  • weekend

    An array of integers indicating the weekend days for the locale, where 1 is Monday and 7 is Sunday.

  • minimalDays

    An integer between 1 and 7 indicating the minimal days required in the first week of a month or year, for calendar purposes.

See also the Unicode LDML specifications

maximise

This is an alias for maximise

maximize

my $english = Locale::Intl->new( 'en' );
my $korean = Locale::Intl->new( 'ko' );
my $arabic = Locale::Intl->new( 'ar' );

say $english->maximize()->baseName;
# en-Latn-US

say $korean->maximize()->baseName;
# ko-Kore-KR

say $arabic->maximize()->baseName;
# ar-Arab-EG

This method gets the most likely values for the language, script, and region of this locale based on existing values and returns a new Locale::Intl object.

Sometimes, it is convenient to be able to identify the most likely locale language identifier subtags based on an incomplete language ID. The Add Likely Subtags algorithm gives us this functionality. For instance, given the language ID en, the algorithm would return en-Latn-US, since English can only be written in the Latin script, and is most likely to be used in the United States, as it is the largest English-speaking country in the world. This functionality is provided via this maximize() method. maximize() only affects the main subtags that comprise the language identifier: language, script, and region subtags. Other subtags after the -u in the locale identifier are called extension subtags and are not affected by the maximize() method. Examples of these subtags include hourCycle, calendar, and numeric.

Upon error, it sets an exception object and returns undef in scalar context, or an empty list in list context.

Example:

my $myLocale = Locale::Intl->new( 'fr', {
    hourCycle => 'h12',
    calendar => 'gregory',
});
say $myLocale->baseName; # fr
say $myLocale->toString(); # fr-u-ca-gregory-hc-h12
my $myLocMaximized = $myLocale->maximize();

# The "Latn" and "FR" tags are added
# fr-Latn-FR
# since French is only written in the Latin script and 
# is most likely to be spoken in France.
say $myLocMaximized->baseName;

# fr-Latn-FR-u-ca-gregory-hc-h12
# Note that the extension tags (after '-u') remain unchanged.
say $myLocMaximized->toString();

minimise

This is an alias for minimise

minimize

my $english = Locale::Intl->new( 'en-Latn-US' );
my $korean = Locale::Intl->new( 'ko-Kore-KR' );
my $arabic = Locale::Intl->new( 'ar-Arab-EG' );

say $english->minimize()->baseName;
# en

say $korean->minimize()->baseName;
# ko

say $arabic->minimize()->baseName;
# ar

my $myLocale = Locale::Intl->new( 'fr-Latn-FR', {
    hourCycle => 'h12',
    calendar => 'gregory',
});
say $myLocale->baseName; # fr-Latn-FR
say $myLocale->toString(); # fr-Latn-FR-u-ca-gregory-hc-h12

my $myLocMinimized = $myLocale->minimize();

# Prints 'fr', since French is only written in the Latin script and
# is most likely to be spoken in France.
say $myLocMinimized->baseName);

# fr-u-ca-gregory-hc-h12
# Note that the extension tags (after '-u') remain unchanged.
say $myLocMinimized->toString();

This method attempts to remove information about this locale that would be added by calling maximize(), which means removing any language, script, or region subtags from the locale language identifier (essentially the contents of baseName).

This is useful when there are superfluous subtags in the language identifier; for instance, en-Latn can be simplified to en, since Latn is the only script used to write English. minimize() only affects the main subtags that comprise the language identifier: language, script, and region subtags. Other subtags after the -u in the locale identifier are called extension subtags and are not affected by the minimize() method. Examples of these subtags include hourCycle, calendar, and numeric.

This returns a new Locale::Intl instance whose baseName property returns the result of the Remove Likely Subtags algorithm executed against $locale->baseName.

toString

my $french = Locale::Intl->new('fr-Latn-FR', {
    calendar => 'gregory',
    hourCycle => 'h12',
});
const korean = Locale::Intl->new('ko-Kore-KR', {
    numeric => 'true',
    caseFirst => 'upper',
});

say $french->toString();
# fr-Latn-FR-u-ca-gregory-hc-h12

say $korean->toString();
# ko-Kore-KR-u-kf-upper-kn

This method returns this Locale::Intl's full locale identifier string.

The string value is computed once and is cached until any of the locale's attributes are changed.

PROPERTIES

baseName

# Sets locale to Canadian French
my $myLoc = Locale::Intl->new( "fr-Latn-CA" );
say $myLoc->toString(); # fr-Latn-CA-u-ca-gregory
say $myLoc->baseName; # fr-Latn-CA

# calendar to Gregorian, hour cycle to 24 hours
my $japan = Locale::Intl->new( "ja-JP-u-ca-gregory-hc-24" );
say $japan->toString(); # ja-JP-u-ca-gregory-hc-h24
$japan->baseName; # ja-JP

# Dutch and region as Belgium, but options override the region to the Netherlands
my $dutch = Locale::Intl->new( "nl-Latn-BE", { region => "NL" });

say $dutch->baseName; # nl-Latn-NL

The baseName accessor property of Locale::Intl instances returns a substring of this locale's string representation, containing core information about this locale.

Specifically, this returns the substring containing the language, the script and region if available.

See Unicode grammar ID for more information.

calendar

This returns the calendar type for this locale.

The calendar property's value is set at object instantiation time, either through the ca attribute of the locale identifier or through the calendar option of the Locale::Unicode constructor. The latter takes priority if they are both present; and if neither is present, the property has value undef.

For a list of supported calendar types, see "getCalendars" in Locale::Intl.

For example:

Adding a calendar through the locale attribute.

In the Unicode locale string specifications, calendar era types are locale attribute "extension subtags". These subtags add additional data about the locale, and are added to locale identifiers by using the -u extension. Thus, the calendar era type can be added to the initial locale identifier string that is passed into the Locale::Intl constructor. To add the calendar type, first add the -u extension to the string. Next, add the -ca extension to indicate that you are adding a calendar type. Finally, add the calendar era type to the string.

my $locale = Locale::Intl->new( 'he-IL-u-ca-hebrew-tz-jeruslm' );
say $locale->calendar; # hebrew

Alternatively, you could also achieve the same results, using the methods inherited from Locale::Unicode:

my $locale = Locale::Intl->new( 'he-IL' );
$locale->ca( 'hebrew' )->tz( 'jeruslm' );
say $locale->calendar; # hebrew

Adding a calendar type via the optional hash or hash reference of options.

The Locale::Intl constructor takes an optional hash or hash reference of options, which can contain any of several extension types, including calendars. Set the calendar property of the optional hash or hash reference to your desired calendar era, and then pass it into the constructor.

my $locale = Locale::Intl->new( 'he-IL', { calendar => 'hebrew' } );
say $locale->calendar; # hebrew

caseFirst

The caseFirst accessor property of Locale::Intl instances returns whether case is taken into account for this locale's collation rules.

There are 3 values that the caseFirst property can have, outlined in the table below.

  • upper

    Upper case to be sorted before lower case.

  • lower

    Lower case to be sorted before upper case.

  • false

    No special case ordering.

Setting the caseFirst value via the locale string

In the Unicode locale string specifications, the values that aseFirst represents correspond to the attribute kf. kf is treated as a locale string "extension subtag". These subtags add additional data about the locale, and are added to locale identifiers by using the -u extension attribute. Thus, the caseFirst value can be added to the initial locale identifier string that is passed into the Locale constructor. To add the caseFirst value, first add the -u extension key to the string. Next, add the -kf extension key to indicate that you are adding a value for caseFirst. Finally, add the caseFirst value to the string.

my $locale = Locale::Intl->new( "fr-Latn-FR-u-kf-upper" );
say $locale->caseFirst; # upper

Setting the caseFirst value via the optional hash or hash reference of options.

The Locale::Intl constructor takes an optional hash or hash reference of options, which can be used to pass extension types. Set the caseFirst property of the configuration object to your desired caseFirst value, and then pass it into the constructor.

my $locale = Locale::Intl->new( "en-Latn-US", { caseFirst => "lower" });
say $locale->caseFirst; # lower

collation

The collation accessor property of Locale::Intl instances returns the collation type for this locale, which is used to order strings according to the locale's rules.

The collation property's value is set at object instantiation time, either through the co attribute of the locale identifier or through the collation option of the Locale::Intl constructor. The latter takes priority if they are both present; and if neither is present, the property has value undef.

For a list of supported collation types, see getCollations().

For example:

Adding a collation type via the locale string.

In the Unicode locale string specifications, collation types are locale attribute "extension subtags". These subtags add additional data about the locale, and are added to locale identifiers by using the -u extension. Thus, the collation type can be added to the initial locale identifier string that is passed into the Locale::Intl constructor. To add the collation type, first add the -u extension to the string. Next, add the -co extension to indicate that you are adding a collation type. Finally, add the collation type to the string.

my $locale = Locale::Intl->new( "zh-Hant-u-co-zhuyin" );
say $locale->collation; # zhuyin

Adding a collation type via the configuration object argument.

The Locale::Intl constructor has an optional hash or hash reference of options, which can contain any of several extension types, including collation types. Set the collation property of the configuration object to your desired collation type, and then pass it into the constructor.

my $locale = Locale::Intl->new( "zh-Hant", { collation => "zhuyin" });
say $locale->collation; # zhuyin

hourCycle

The hourCycle accessor property of Locale::Intl instances returns the hour cycle type for this locale identifier.

There are 2 main types of time keeping conventions (clocks) used around the world: the 12 hour clock and the 24 hour clock. The hourCycle property's value is set upon object instantiation, either through the hc attribute of the locale identifier or through the hourCycle option of the Locale::Intl constructor. The latter takes priority if they are both present; and if neither is present, the property has value undef.

For a list of supported hour cycle types, see getHourCycles().

For example:

Like other locale subtags, the hour cycle type can be added to the Locale::Intl object via the locale string, or an option upon object instantiation.

Adding an hour cycle via the locale string

In the Unicode locale string specifications, hour cycle types are locale attribute "extension subtags". These subtags add additional data about the locale, and are added to locale identifiers by using the -u extension. Thus, the hour cycle type can be added to the initial locale identifier string that is passed into the Locale::Intl constructor. To add the hour cycle type, first add the -u extension key to the string. Next, add the -hc extension to indicate that you are adding an hour cycle. Finally, add the hour cycle type to the string.

my $locale = Locale::Intl->new( "fr-FR-u-hc-h23" );
say $locale->hourCycle; # h23

Adding an hour cycle via the configuration object argument

The Locale::Intl constructor has an optional hash or hash reference of options, which can contain any of several extension types, including hour cycle types. Set the hourCycle property of the configuration object to your desired hour cycle type, and then pass it into the constructor.

my $locale = Locale::Intl->new( "en-US", { hourCycle => "h12" });
say $locale->hourCycle; # h12

language

The language accessor property of Locale::Intl instances returns the language associated with this locale.

Language is one of the core features of a locale. The Unicode specification treats the language identifier of a locale as the language and the region together (to make a distinction between dialects and variations, e.g. British English vs. American English). However, the language property of an Locale::Intl object returns strictly the locale's language subtag. This subtag can be a 2 or 3-characters code.

For example:

Setting the language in the locale identifier string argument.

In order to be a valid Unicode locale identifier, a string must start with the language subtag. The main argument to the Locale::Intl constructor must be a valid Unicode locale identifier, so whenever the constructor is used, it must be passed an identifier with a language subtag.

my $locale = Locale::Intl->new( "en-Latn-US" );
say $locale->language; # en

Overriding language via the configuration object.

While the language subtag must be specified, the Locale::Intl constructor takes an hash or hash reference of options, which can override the language subtag.

my $locale = Locale::Intl->new( "en-Latn-US", { language => "es" });
say $locale->language; # es

numberingSystem

The numberingSystem accessor property of Locale::Intl instances returns the numeral system for this locale.

A numeral system is a system for expressing numbers. The numberingSystem property's value is set upon object instantiation, either through the nu attribute of the locale identifier or through the numberingSystem option of the Locale::Intl constructor. The latter takes priority if they are both present; and if neither is present, the property has value undef.

For a list of supported numbering system types, see getNumberingSystems().

Adding a numbering system via the locale string.

In the Unicode locale string specifications, numbering system types are locale attribute "extension subtags". These subtags add additional data about the locale, and are added to locale identifiers by using the -u extension. Thus, the numbering system type can be added to the initial locale identifier string that is passed into the Locale::Intl constructor. To add the numbering system type, first add the -u extension attribute to the string. Next, add the -nu extension to indicate that you are adding a numbering system. Finally, add the numbering system type to the string.

my $locale = Locale::Intl->new( "fr-Latn-FR-u-nu-mong" );
say $locale->numberingSystem; # mong

Adding a numbering system via the configuration object argument.

The Locale::Intl constructor has an optional hash or hash reference of options, which can contain any of several extension types, including numbering system types. Set the numberingSystem property of the hash or hash reference of options to your desired numbering system type, and then pass it into the constructor.

my $locale = Locale::Intl->new( "en-Latn-US", { numberingSystem => "latn" });
say $locale->numberingSystem; # latn

numeric

The numeric accessor property of Locale::Intl instances returns a boolean object representing whether this locale has special collation handling for numeric characters.

Like caseFirst, numeric represents a modification to the collation rules utilized by the locale. numeric is a boolean value, which means that it can be either true or false. If numeric is set to false, there will be no special handling of numeric values in strings. If numeric is set to true, then the locale will take numeric characters into account when collating strings. This special numeric handling means that sequences of decimal digits will be compared as numbers. For example, the string A-21 will be considered less than A-123.

Example:

Setting the numeric value via the locale string.

In the Unicode locale string specifications, the values that numeric represents correspond to the attribute kn. kn is considered a locale string extension subtag". These subtags add additional data about the locale, and are added to locale identifiers by using the -u extension key. Thus, the numeric value can be added to the initial locale identifier string that is passed into the Locale::Intl constructor. To set the numeric value, first add the -u extension attribute to the string. Next, add the -kn extension attribute to indicate that you are adding a value for numeric. Finally, add the numeric value to the string. If you want to set numeric to true, adding the kn attribute will suffice. To set the value to false, you must specify in by adding "false" after the kn attribute.

my $locale = Locale::Intl->new("fr-Latn-FR-u-kn-false");
say $locale->numeric); # false

Setting the numeric value via the configuration object argument.

The Locale::Unicode constructor has an optional hash or hash reference of options, which can be used to pass extension types. Set the numeric property of the hash or hash reference of options to your desired numeric value and pass it into the constructor.

my $locale = Locale::Intl->new("en-Latn-US", { numeric => $true_value });
say $locale->numeric; # true

region

The region accessor property of Locale::Intl instances returns the region of the world (usually a country) associated with this locale. This could be a country code, or a world region represented with a 3-digits code

The region is an essential part of the locale identifier, as it places the locale in a specific area of the world. Knowing the locale's region is vital to identifying differences between locales. For example, English is spoken in the United Kingdom and the United States of America, but there are differences in spelling and other language conventions between those two countries.

For example:

Setting the region in the locale identifier string argument.

The region is the third part of a valid Unicode language identifier string, and can be set by adding it to the locale identifier string that is passed into the Locale::Intl constructor.

my $locale = Locale::Intl->new( "en-Latn-US" );
say $locale->region; # US

my $locale = Locale::Intl->new( "fr-Latn-150" );
say $locale->region; # 150
# 150 is the region code for Europe

See the file territories.json in the CLDR repository for the localised names of those territories.

script

The script accessor property of Locale::Intl instances returns the script used for writing the particular language used in this locale.

A script, sometimes called writing system, is one of the core attributes of a locale. It indicates the set of symbols, or glyphs, that are used to write a particular language. For instance, the script associated with English is Latin (latn), whereas the script used to represent Japanese Katanaka is Kana and the one typically associated with Korean is Hangul (Hang). In many cases, denoting a script is not strictly necessary, since the language (which is necessary) is only written in a single script. There are exceptions to this rule, however, and it is important to indicate the script whenever possible, in order to have a complete Unicode language identifier.

For example:

Setting the script in the locale identifier string argument.

The script is the second part of a valid Unicode language identifier string, and can be set by adding it to the locale identifier string that is passed into the Locale::Intl constructor. Note that the script is not a required part of a locale identifier.

my $locale = Locale::Intl->new( "en-Latn-US" );
say $locale->script); # Latn

Setting the script via the hash or hash reference of options.

The Locale::Intl constructor takes an hash or hash reference of options, which can be used to set the script subtag and property.

my $locale = Locale::Intl->new("fr-FR", { script => "Latn" });
say $locale; # fr-Latn-FR
say $locale->script; # Latn

OVERLOADING

Instances of Locale::Intl have the stringification overloaded as inherited from Locale::Unicode

AUTHOR

Jacques Deguest <jack@deguest.jp>

SEE ALSO

DateTime::Format::Intl

CREDITS

Credits to Mozilla for parts of their documentation I copied here.

COPYRIGHT & LICENSE

Copyright(c) 2024 DEGUEST Pte. Ltd.

All rights reserved

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