vendor/rails/activesupport/lib/active_support/vendor/i18n-0.1.3/lib/i18n.rb

   1 # Authors::   Matt Aimonetti (http://railsontherun.com/),
   2 #             Sven Fuchs (http://www.artweb-design.de),
   3 #             Joshua Harvey (http://www.workingwithrails.com/person/759-joshua-harvey),
   4 #             Saimon Moore (http://saimonmoore.net),
   5 #             Stephan Soller (http://www.arkanis-development.de/)
   6 # Copyright:: Copyright (c) 2008 The Ruby i18n Team
   7 # License::   MIT
   8 require 'i18n/backend/simple'
   9 require 'i18n/exceptions'
  10
  11 module I18n
  12   @@backend = nil
  13   @@load_path = nil
  14   @@default_locale = :'en'
  15   @@exception_handler = :default_exception_handler
  16
  17   class << self
  18     # Returns the current backend. Defaults to +Backend::Simple+.
  19     def backend
  20       @@backend ||= Backend::Simple.new
  21     end
  22
  23     # Sets the current backend. Used to set a custom backend.
  24     def backend=(backend)
  25       @@backend = backend
  26     end
  27
  28     # Returns the current default locale. Defaults to :'en'
  29     def default_locale
  30       @@default_locale
  31     end
  32
  33     # Sets the current default locale. Used to set a custom default locale.
  34     def default_locale=(locale)
  35       @@default_locale = locale
  36     end
  37
  38     # Returns the current locale. Defaults to I18n.default_locale.
  39     def locale
  40       Thread.current[:locale] ||= default_locale
  41     end
  42
  43     # Sets the current locale pseudo-globally, i.e. in the Thread.current hash.
  44     def locale=(locale)
  45       Thread.current[:locale] = locale
  46     end
  47
  48     # Returns an array of locales for which translations are available
  49     def available_locales
  50       backend.available_locales
  51     end
  52
  53     # Sets the exception handler.
  54     def exception_handler=(exception_handler)
  55       @@exception_handler = exception_handler
  56     end
  57
  58     # Allow clients to register paths providing translation data sources. The
  59     # backend defines acceptable sources.
  60     #
  61     # E.g. the provided SimpleBackend accepts a list of paths to translation
  62     # files which are either named *.rb and contain plain Ruby Hashes or are
  63     # named *.yml and contain YAML data. So for the SimpleBackend clients may
  64     # register translation files like this:
  65     #   I18n.load_path << 'path/to/locale/en.yml'
  66     def load_path
  67       @@load_path ||= []
  68     end
  69
  70     # Sets the load path instance. Custom implementations are expected to
  71     # behave like a Ruby Array.
  72     def load_path=(load_path)
  73       @@load_path = load_path
  74     end
  75
  76     # Tells the backend to reload translations. Used in situations like the
  77     # Rails development environment. Backends can implement whatever strategy
  78     # is useful.
  79     def reload!
  80       backend.reload!
  81     end
  82
  83     # Translates, pluralizes and interpolates a given key using a given locale,
  84     # scope, and default, as well as interpolation values.
  85     #
  86     # *LOOKUP*
  87     #
  88     # Translation data is organized as a nested hash using the upper-level keys
  89     # as namespaces. <em>E.g.</em>, ActionView ships with the translation:
  90     # <tt>:date => {:formats => {:short => "%b %d"}}</tt>.
  91     #
  92     # Translations can be looked up at any level of this hash using the key argument
  93     # and the scope option. <em>E.g.</em>, in this example <tt>I18n.t :date</tt>
  94     # returns the whole translations hash <tt>{:formats => {:short => "%b %d"}}</tt>.
  95     #
  96     # Key can be either a single key or a dot-separated key (both Strings and Symbols
  97     # work). <em>E.g.</em>, the short format can be looked up using both:
  98     #   I18n.t 'date.formats.short'
  99     #   I18n.t :'date.formats.short'
 100     #
 101     # Scope can be either a single key, a dot-separated key or an array of keys
 102     # or dot-separated keys. Keys and scopes can be combined freely. So these
 103     # examples will all look up the same short date format:
 104     #   I18n.t 'date.formats.short'
 105     #   I18n.t 'formats.short', :scope => 'date'
 106     #   I18n.t 'short', :scope => 'date.formats'
 107     #   I18n.t 'short', :scope => %w(date formats)
 108     #
 109     # *INTERPOLATION*
 110     #
 111     # Translations can contain interpolation variables which will be replaced by
 112     # values passed to #translate as part of the options hash, with the keys matching
 113     # the interpolation variable names.
 114     #
 115     # <em>E.g.</em>, with a translation <tt>:foo => "foo {{bar}}"</tt> the option
 116     # value for the key +bar+ will be interpolated into the translation:
 117     #   I18n.t :foo, :bar => 'baz' # => 'foo baz'
 118     #
 119     # *PLURALIZATION*
 120     #
 121     # Translation data can contain pluralized translations. Pluralized translations
 122     # are arrays of singluar/plural versions of translations like <tt>['Foo', 'Foos']</tt>.
 123     #
 124     # Note that <tt>I18n::Backend::Simple</tt> only supports an algorithm for English
 125     # pluralization rules. Other algorithms can be supported by custom backends.
 126     #
 127     # This returns the singular version of a pluralized translation:
 128     #   I18n.t :foo, :count => 1 # => 'Foo'
 129     #
 130     # These both return the plural version of a pluralized translation:
 131     #   I18n.t :foo, :count => 0 # => 'Foos'
 132     #   I18n.t :foo, :count => 2 # => 'Foos'
 133     #
 134     # The <tt>:count</tt> option can be used both for pluralization and interpolation.
 135     # <em>E.g.</em>, with the translation
 136     # <tt>:foo => ['{{count}} foo', '{{count}} foos']</tt>, count will
 137     # be interpolated to the pluralized translation:
 138     #   I18n.t :foo, :count => 1 # => '1 foo'
 139     #
 140     # *DEFAULTS*
 141     #
 142     # This returns the translation for <tt>:foo</tt> or <tt>default</tt> if no translation was found:
 143     #   I18n.t :foo, :default => 'default'
 144     #
 145     # This returns the translation for <tt>:foo</tt> or the translation for <tt>:bar</tt> if no
 146     # translation for <tt>:foo</tt> was found:
 147     #   I18n.t :foo, :default => :bar
 148     #
 149     # Returns the translation for <tt>:foo</tt> or the translation for <tt>:bar</tt>
 150     # or <tt>default</tt> if no translations for <tt>:foo</tt> and <tt>:bar</tt> were found.
 151     #   I18n.t :foo, :default => [:bar, 'default']
 152     #
 153     # <b>BULK LOOKUP</b>
 154     #
 155     # This returns an array with the translations for <tt>:foo</tt> and <tt>:bar</tt>.
 156     #   I18n.t [:foo, :bar]
 157     #
 158     # Can be used with dot-separated nested keys:
 159     #   I18n.t [:'baz.foo', :'baz.bar']
 160     #
 161     # Which is the same as using a scope option:
 162     #   I18n.t [:foo, :bar], :scope => :baz
 163     def translate(key, options = {})
 164       locale = options.delete(:locale) || I18n.locale
 165       backend.translate(locale, key, options)
 166     rescue I18n::ArgumentError => e
 167       raise e if options[:raise]
 168       send(@@exception_handler, e, locale, key, options)
 169     end
 170     alias :t :translate
 171
 172     # Localizes certain objects, such as dates and numbers to local formatting.
 173     def localize(object, options = {})
 174       locale = options[:locale] || I18n.locale
 175       format = options[:format] || :default
 176       backend.localize(locale, object, format)
 177     end
 178     alias :l :localize
 179
 180   protected
 181     # Handles exceptions raised in the backend. All exceptions except for
 182     # MissingTranslationData exceptions are re-raised. When a MissingTranslationData
 183     # was caught and the option :raise is not set the handler returns an error
 184     # message string containing the key/scope.
 185     def default_exception_handler(exception, locale, key, options)
 186       return exception.message if MissingTranslationData === exception
 187       raise exception
 188     end
 189
 190     # Merges the given locale, key and scope into a single array of keys.
 191     # Splits keys that contain dots into multiple keys. Makes sure all
 192     # keys are Symbols.
 193     def normalize_translation_keys(locale, key, scope)
 194       keys = [locale] + Array(scope) + [key]
 195       keys = keys.map { |k| k.to_s.split(/\./) }
 196       keys.flatten.map { |k| k.to_sym }
 197     end
 198   end
 199 end