vendor/rails/activesupport/lib/active_support/vendor/i18n-0.0.1/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     # Sets the exception handler.
  49     def exception_handler=(exception_handler)
  50       @@exception_handler = exception_handler
  51     end
  52
  53     # Allow clients to register paths providing translation data sources. The
  54     # backend defines acceptable sources.
  55     #
  56     # E.g. the provided SimpleBackend accepts a list of paths to translation
  57     # files which are either named *.rb and contain plain Ruby Hashes or are
  58     # named *.yml and contain YAML data. So for the SimpleBackend clients may
  59     # register translation files like this:
  60     #   I18n.load_path << 'path/to/locale/en.yml'
  61     def load_path
  62       @@load_path ||= []
  63     end
  64
  65     # Sets the load path instance. Custom implementations are expected to
  66     # behave like a Ruby Array.
  67     def load_path=(load_path)
  68       @@load_path = load_path
  69     end
  70
  71     # Tells the backend to reload translations. Used in situations like the
  72     # Rails development environment. Backends can implement whatever strategy
  73     # is useful.
  74     def reload!
  75       backend.reload!
  76     end
  77
  78     # Translates, pluralizes and interpolates a given key using a given locale,
  79     # scope, and default, as well as interpolation values.
  80     #
  81     # *LOOKUP*
  82     #
  83     # Translation data is organized as a nested hash using the upper-level keys
  84     # as namespaces. <em>E.g.</em>, ActionView ships with the translation:
  85     # <tt>:date => {:formats => {:short => "%b %d"}}</tt>.
  86     #
  87     # Translations can be looked up at any level of this hash using the key argument
  88     # and the scope option. <em>E.g.</em>, in this example <tt>I18n.t :date</tt>
  89     # returns the whole translations hash <tt>{:formats => {:short => "%b %d"}}</tt>.
  90     #
  91     # Key can be either a single key or a dot-separated key (both Strings and Symbols
  92     # work). <em>E.g.</em>, the short format can be looked up using both:
  93     #   I18n.t 'date.formats.short'
  94     #   I18n.t :'date.formats.short'
  95     #
  96     # Scope can be either a single key, a dot-separated key or an array of keys
  97     # or dot-separated keys. Keys and scopes can be combined freely. So these
  98     # examples will all look up the same short date format:
  99     #   I18n.t 'date.formats.short'
 100     #   I18n.t 'formats.short', :scope => 'date'
 101     #   I18n.t 'short', :scope => 'date.formats'
 102     #   I18n.t 'short', :scope => %w(date formats)
 103     #
 104     # *INTERPOLATION*
 105     #
 106     # Translations can contain interpolation variables which will be replaced by
 107     # values passed to #translate as part of the options hash, with the keys matching
 108     # the interpolation variable names.
 109     #
 110     # <em>E.g.</em>, with a translation <tt>:foo => "foo {{bar}}"</tt> the option
 111     # value for the key +bar+ will be interpolated into the translation:
 112     #   I18n.t :foo, :bar => 'baz' # => 'foo baz'
 113     #
 114     # *PLURALIZATION*
 115     #
 116     # Translation data can contain pluralized translations. Pluralized translations
 117     # are arrays of singluar/plural versions of translations like <tt>['Foo', 'Foos']</tt>.
 118     #
 119     # Note that <tt>I18n::Backend::Simple</tt> only supports an algorithm for English
 120     # pluralization rules. Other algorithms can be supported by custom backends.
 121     #
 122     # This returns the singular version of a pluralized translation:
 123     #   I18n.t :foo, :count => 1 # => 'Foo'
 124     #
 125     # These both return the plural version of a pluralized translation:
 126     #   I18n.t :foo, :count => 0 # => 'Foos'
 127     #   I18n.t :foo, :count => 2 # => 'Foos'
 128     #
 129     # The <tt>:count</tt> option can be used both for pluralization and interpolation.
 130     # <em>E.g.</em>, with the translation
 131     # <tt>:foo => ['{{count}} foo', '{{count}} foos']</tt>, count will
 132     # be interpolated to the pluralized translation:
 133     #   I18n.t :foo, :count => 1 # => '1 foo'
 134     #
 135     # *DEFAULTS*
 136     #
 137     # This returns the translation for <tt>:foo</tt> or <tt>default</tt> if no translation was found:
 138     #   I18n.t :foo, :default => 'default'
 139     #
 140     # This returns the translation for <tt>:foo</tt> or the translation for <tt>:bar</tt> if no
 141     # translation for <tt>:foo</tt> was found:
 142     #   I18n.t :foo, :default => :bar
 143     #
 144     # Returns the translation for <tt>:foo</tt> or the translation for <tt>:bar</tt>
 145     # or <tt>default</tt> if no translations for <tt>:foo</tt> and <tt>:bar</tt> were found.
 146     #   I18n.t :foo, :default => [:bar, 'default']
 147     #
 148     # <b>BULK LOOKUP</b>
 149     #
 150     # This returns an array with the translations for <tt>:foo</tt> and <tt>:bar</tt>.
 151     #   I18n.t [:foo, :bar]
 152     #
 153     # Can be used with dot-separated nested keys:
 154     #   I18n.t [:'baz.foo', :'baz.bar']
 155     #
 156     # Which is the same as using a scope option:
 157     #   I18n.t [:foo, :bar], :scope => :baz
 158     def translate(key, options = {})
 159       locale = options.delete(:locale) || I18n.locale
 160       backend.translate(locale, key, options)
 161     rescue I18n::ArgumentError => e
 162       raise e if options[:raise]
 163       send(@@exception_handler, e, locale, key, options)
 164     end
 165     alias :t :translate
 166
 167     # Localizes certain objects, such as dates and numbers to local formatting.
 168     def localize(object, options = {})
 169       locale = options[:locale] || I18n.locale
 170       format = options[:format] || :default
 171       backend.localize(locale, object, format)
 172     end
 173     alias :l :localize
 174
 175   protected
 176     # Handles exceptions raised in the backend. All exceptions except for
 177     # MissingTranslationData exceptions are re-raised. When a MissingTranslationData
 178     # was caught and the option :raise is not set the handler returns an error
 179     # message string containing the key/scope.
 180     def default_exception_handler(exception, locale, key, options)
 181       return exception.message if MissingTranslationData === exception
 182       raise exception
 183     end
 184
 185     # Merges the given locale, key and scope into a single array of keys.
 186     # Splits keys that contain dots into multiple keys. Makes sure all
 187     # keys are Symbols.
 188     def normalize_translation_keys(locale, key, scope)
 189       keys = [locale] + Array(scope) + [key]
 190       keys = keys.map { |k| k.to_s.split(/\./) }
 191       keys.flatten.map { |k| k.to_sym }
 192     end
 193   end
 194 end