NAME

Data::Localize - Alternate Data Localization API

SYNOPSIS

use Data::Localize;

my $loc = Data::Localize->new();
$loc->add_localizer(
    class      => "Namespace", # Locale::Maketext-style .pm files
    namespaces => [ "MyApp::I18N" ]
);

$loc->add_localizer( 
    class => "Gettext",
    path  => "/path/to/localization/data/*.po"
);

$loc->set_languages();
# or explicitly set one
# $loc->set_languages('en', 'ja' );

# looks under $self->languages, and checks if there are any
# localizers that can handle the job
$loc->localize( 'Hellow, [_1]!', 'John Doe' );

# You can enable "auto", which will be your last resort fallback.
# The key you give to the localize method will be used as the lexicon
$self->auto(1);

DESCRIPTION

Data::Localize is an object oriented approach to localization, aimed to be an alternate choice for Locale::Maketext, Locale::Maketext::Lexicon, and Locale::Maketext::Simple.

RATIONALE

Functionality-wise, Locale::Maketext does what it advertises to do. Here's a few reasons why you might or might not choose Data::Localize over Locale::Maketext-based localizers:

Object-Oriented

Data::Localize is completely object-oriented. YMMV.

Faster

On some my benchmarks, Data::Localize is faster than Locale::Maketext by 50~80%. (But see PERFORMANCE)

Scalable For Large Amount Of Lexicons

Whereas Locale::Maketext generally stores the lexicons in memory, Data::Localize allows you to store this data in alternate storage. By default Data::Localize comes with a BerkeleyDB backend.

BASIC WORKING

STRUCTURE

Data::Localize is a wrapper around various Data::Localize::Localizer implementers (localizers). So if you don't specify any localizers, Data::Localize will do... nothing (unless you specify auto).

Localizers are the objects that do the actual localization. Localizers must register themselves to the Data::Localize parent, noting which languages it can handle (which usually is determined by the presence of data files like en.po, ja.po, etc). A special language ID of '*' is used to accept fallback cases. Localizers registered to handle '*' will be tried after all other language possibilities have been exhausted.

If the particular localizer cannot deal with the requested string, then it simply returns nothing.

AUTO-GENERATING LEXICONS

Locale::Maketext allows you to supply an "_AUTO" key in the lexicon hash, which allows you to pass a non-existing key to the localize() method, and use it as the actual lexicon, if no other applicable lexicons exists.

Locale::Maketext attaches this to the lexicon hash itself, but Data::Localizer differs in that it attaches to the Data::Localizer object itself, so you don't have to place _AUTO everywhere.

# here, we're deliberately not setting any localizers
my $loc = Data::Localize->new(auto => 1);

# previous auto => 1 will force Data::Localize to fallback to
# using the key ('Hello, [_1]') as the localization token.
print $loc->localize('Hello, [_1]', 'John Doe'), "\n";

UTF8

All data is expected to be in decoded utf8. You must "use utf8" or decode them to Perl's internal representation for all values passed to Data::Localizer. We won't try to be smart for you. USE UTF8!

Using Explicit decode()

  use Encode q(decode decode_utf8);
  use Data::Localizer;

  my $loc = Data::Localize->new(...);

  $loc->localize( $key, decode( 'iso-2022-jp', $value ) );

  # if $value is encoded utf8...
  # $loc->localize( $key, decode_utf8( $value ) );

Using utf8

"use utf8" is simpler, but do note that it will affect ALL your literal strings in the current scope
```
  use utf8;

  $loc->localize( $key, "some-utf8-key-here" );
```

USING ALTERNATE STORAGE

By default all lexicons are stored on memory, but if you're building an app with thousands and thousands of long messages, this might not be the ideal solution. In such cases, you can change where the lexicons get stored

my $loc = Data::Localize->new();
$loc->add_localizer(
    class         => 'Gettext',
    path          => '/path/to/data/*.po'
    storage_class => 'BerkeleyDB',
    storage_args  => {
        dir => '/path/to/really/fast/device'
    }
);

This would cause Data::Localize to put all the lexicon data in several BerkeleyDB files under /path/to/really/fast/device

Note that this approach would buy you no gain if you use Data::Localize::Namespace, as that approach by default expects everything to be in memory.

DEBUGGING

DEBUG

To enable debug tracing, either set DATA_LOCALIZE_DEBUG environment variable,

DATA_LOCALIZE_DEBUG=1 ./yourscript.pl

or explicitly define a function before loading Data::Localize:

BEGIN {
    *Data::Localize::DEBUG = sub () { 1 };
}
use Data::Localize;

METHODS

add_localizer

Adds a new localizer. You may either pass a localizer object, or arguments to your localizer's constructor:

$loc->add_localizer( YourLocalizer->new );

$loc->add_localizer(
    class => "Namespace",
    namespaces => [ 'Blah' ]
);

localize

Localize the given string ID, using provided variables.

$localized_string = $loc->localize( $id, @args );

detect_languages

Detects the current set of languages to use. If used in an CGI environment, will attempt to detect the language of choice from headers. See I18N::LanguageTags::Detect for details.

detect_languages_from_header

Detects the language from the given header value, or from HTTP_ACCEPT_LANGUAGES environment variable

localizers

Return a arrayref of localizers

add_localizer_map

Used internally.

set_localizer_map

Used internally.

find_localizers

Finds a localizer by its attribute. Currently only supports isa

my @locs = $loc->find_localizers(isa => 'Data::Localize::Gettext');

set_languages

If used without any arguments, calls detect_languages() and sets the current language set to the result of detect_languages().

languages

Gets the current list of languages

add_fallback_languages

fallback_languages

count_localizers()

Return the number of localizers available

get_localizer_from_lang($lang)

Get appropriate localizer for language $lang

grep_localizers(\&sub)

Filter localizers

PERFORMANCE

tl;dr: Use one that fits your needs

Using explicit get_handle for every request

This benchmark assumes that you're fetching the lexicon anew for every request. This allows you to switch languages for every request

Benchmark run with Mac OS X (10.8.2) perl 5.16.1

Running benchmarks with
  Locale::Maketext: 1.23
  Data::Localize:   0.00023
                     Rate D::L(Namespace)   L::M D::L(Gettext) D::L(Gettext+BDB)
D::L(Namespace)    5051/s              --   -65%          -73%              -73%
L::M              14423/s            186%     --          -24%              -24%
D::L(Gettext)     18868/s            274%    31%            --               -1%
D::L(Gettext+BDB) 18987/s            276%    32%            1%                --

Using cached lexicon objects for all

This benchmark assumes that you're fetching the lexicon once for a particular language, and you keep it in memory for reuse. This does NOT allow you to switch languages for every request.