This document summarizes PHP's Internationalization (intl) extension, which provides localization and internationalization functions based on the ICU library. It covers key classes like Collator for string comparison, NumberFormatter for number formatting, MessageFormatter for message formatting, and IntlDateFormatter for date/time formatting. Functions for locales, Unicode normalization, grapheme handling, and IDN are also described. The goal of the intl extension is to provide robust i18n/l10n capabilities to PHP applications using standardized ICU implementations.

1. PHP Internationalization with ICU By Stas Malyshev, Zend Technologies

2. What and why? ICU - http://icu-project.org/ (IBM) Unicode CLDR - http://cldr.unicode.org/

3. Intl extension Locale Collator Number & Currency formatter Date & Time formatter Message & Choice formatter Normalizer Graphemes IDN Calendars Resources

4. Intl extension Dual API OO and procedural Same implementation underneath collator_create () == new Collator () numfmt_format () == NumberFormatter::format () locale_get_default () == Locale::getDefault ()

5. Locale Relies on ICU locales <language>[_<script>]_<country>[_<variant>][@<keywords>] Default locale new Collator(Locale::DEFAULT ) Locale::setDefault, Locale::getDefault You can use null

6. Locale Locale pieces getPrimaryLanguage($locale) getScript($locale) getRegion($locale) getVariant($locale) getKeywords($locale)

7. Locale Locale display pieces getDisplayName($locale, $in_locale = null) getDisplayLanguage($locale, $in_locale = null) getDisplayScript($locale, $in_locale = null) getDisplayRegion($locale, $in_locale = null) Example: getDisplayScript(getScript(&quot;zh-Hant-TW&quot;), &quot;en-US&quot;) returns “Traditional Chinese”

8. Locale building blocks parseLocale () - returns array composed of locale subtags composeLocale () - creates locale ID out of subtags parseLocale('sr-Latn-RS') returns array('language'=>'sr', 'script'=>'Latn', 'region'=>’RS’) composeLocale(array('language'=>'sr', 'script'=>'Latn', 'region'=>’RS’)) returns ‘sr-Latn-RS ’

9. Locale guessing acceptFromHttp - Accept-Language to locale lookup – find in the list filterMatches – are they the same?

10. Collator Comparing, sorting strings Collation level (strength) All ICU collator attributes Numeric collation Ignoring punctuation Not yet: custom “tailoring” rules

11. Collator $coll = new Collator ( &quot;fr_CA&quot; ); if ( $coll -> compare ( &quot;côte&quot; , &quot;coté&quot; ) < 0 ) { echo &quot;less\n&quot; ; } else { echo &quot;greater\n&quot; ; } côte < coté

12. Collator $strings = array( &quot;cote&quot; , &quot;côte&quot; , &quot;Côte&quot; , &quot;coté&quot; , &quot;Coté&quot; , &quot;côté&quot; , &quot;Côté&quot; , &quot;coter&quot; ); $coll = new Collator ( &quot;fr_CA&quot; ); $coll -> sort ( $strings ); cote côte Côte coté Coté côté Côté coter sort($array, $flags) asort($array, $flags) sortWithSortKeys($array)

13. NumberFormatter Formatting and parsing Numbers and currency numfmt_create($locale, $style, $pattern = null) NumberFormatter::PATTERN_DECIMAL NumberFormatter::ORDINAL NumberFormatter::DECIMAL NumberFormatter::DURATION NumberFormatter::CURRENCY NumberFormatter::SCIENTIFIC NumberFormatter::PERCENT NumberFormatter::SPELLOUT

14. NumberFormatter Formatting $fmt = new NumberFormatter ( ‘en_US’ , NumberFormatter :: DECIMAL ); echo $fmt -> format ( 1234 ); // result is 1,234 $fmt = new NumberFormatter ( ‘de_CH’ , NumberFormatter :: DECIMAL ); echo $fmt -> format ( 1234 ); // result is 1'234

15. NumberFormatter Parsing $fmt = new NumberFormatter ( ‘de_DE’ , NumberFormatter :: DECIMAL ); $num = ‘1.234 , 567 min’ ; $fmt -> parse ( $num , NumberFormatter :: TYPE_DOUBLE , $pos ); // result is 1234.567 , $pos = 9 $fmt -> parse ( $num , NumberFormatter :: TYPE_INT32 ); // result is 1234

16. MessageFormatter Formatting and parsing whole messages, including data inside Also allows choice between things printed: 0≤are no files|1≤is one file|1<are many files

17. MessageFormatter $fmt = new MessageFormatter ( &quot;en_US&quot; , &quot;{0,number,integer} monkeys on {1,number,integer} trees make {2,number} monkeys per tree&quot; ); echo $fmt -> format (array( 4560 , 123 , 4560 / 123 )); $fmt = new MessageFormatter ( &quot;de&quot; , &quot;{0,number,integer} Affen über {1,number,integer} Bäume um {2,number} Affen pro Baum&quot; ); echo $fmt -> format (array( 4560 , 123 , 4560 / 123 ));

18. IntlDateFormatter Allows using locale-dependent canned patterns Short, medium, long date & time Long: Tuesday, April 12, 1952 AD or 3:30:42pm PST Medium: January 12, 1952 or 3:30:32pm Short: 12/13/52 or 3:30pm Also allows free-form patterns &quot;yyyy.MM.dd G 'at' HH:mm:ss vvvv&quot; 1996.07.10 AD at 15:08:56 Pacific Time

19. IntlDateFormatter $fmt = new IntlDateFormatter ( &quot;en_US&quot; , IntlDateFormatter :: FULL , IntlDateFormatter :: FULL , 'America/Los_Angeles' , IntlDateFormatter :: GREGORIAN ); echo $fmt -> format ( 0 ); // Wednesday, December 31, 1969 4:00:00 PM PT $fmt = new IntlDateFormatter ( &quot;de-DE&quot; , IntlDateFormatter :: FULL , IntlDateFormatter :: FULL , 'America/Los_Angeles' , IntlDateFormatter :: GREGORIAN ); echo $fmt -> format ( 0 ); // Mittwoch, 31. Dezember 1969 16:00 Uhr GMT-08:00

20. Normalizer Brings Unicode text to one of the normal forms: NFC, NFD, NFKC, NFKD normalize(), isNormalized() $combining_ring_above = &quot;\xCC\x8A&quot; ; // 'COMBINING RING ABOVE' (U+030A) $chars = Normalizer :: normalize ( 'A' . $combining_ring_above , Normalizer :: FORM_C ); echo urlencode ( $chars ); // %C3%85 i.e. // 'LATIN CAPITAL LETTER A WITH RING ABOVE' (U+00C5)

21. Grapheme functions Graphemes are multi-char entities, like letter + accent mark(s) Same as string functions, but operate on grapheme units Strlen, substr, strpos, strstr Extraction function – extract to fill limited buffer, but always keep graphemes whole

22. IDN עברית .idn.icann.org ↔ xn--5dbqzzl.idn.icann.org русский.idn.icann.org ↔ xn--h1acbxfam.idn.icann.org idn_to_ascii idn_to_utf8

23. TODO ResourceHandler Transliteration StringSearch Tighter integration with other modules in 6.0

24. Thanks! http://php.net/intl for futher information.