Use I18n and add Japanese locale.

Gemfile

@@ -1,3 +1,3 @@
 source 'https://rubygems.org'
 
-gemspec
+gemspec

config/locales/en.yml

@@ -0,0 +1,116 @@
+en:
+  ice_cube:
+    pieces_connector: ' / '
+    not: 'not %{target}'
+    not_on: 'not on %{target}'
+    date:
+      formats:
+        default: '%B %-d, %Y'
+      month_names:
+      -
+      - January
+      - February
+      - March
+      - April
+      - May
+      - June
+      - July
+      - August
+      - September
+      - October
+      - November
+      - December
+      day_names:
+      - Sunday
+      - Monday
+      - Tuesday
+      - Wednesday
+      - Thursday
+      - Friday
+      - Saturday
+    times:
+      other: '%{count} times'
+      one: '%{count} time'
+    until: 'until %{date}'
+    days_of_week: '%{segments} %{day}'
+    days_of_month:
+      other: '%{segments} days of the month'
+      one: '%{segments} day of the month'
+    days_of_year:
+      other: '%{segments} days of the year'
+      one: '%{segments} day of the year'
+    at_hours_of_the_day:
+      other: on the %{segments} hours of the day
+      one: on the %{segments} hour of the day
+    on_minutes_of_hour:
+      other: on the %{segments} minutes of the hour
+      one: on the %{segments} minute of the hour
+    at_seconds_of_minute:
+      other: at the %{segments} seconds
+      one: at the %{segments} second
+    on_seconds_of_minute:
+      other: on the %{segments} seconds of the minute
+      one: on the %{segments} second of the minute
+    each_second:
+      one: Secondly
+      other: Every %{count} seconds
+    each_minute:
+      one: Minutely
+      other: Every %{count} minutes
+    each_hour:
+      one: Hourly
+      other: Every %{count} hours
+    each_day:
+      one: Daily
+      other: Every %{count} days
+    each_week:
+      one: Weekly
+      other: Every %{count} weeks
+    each_month:
+      one: Monthly
+      other: Every %{count} months
+    each_year:
+      one: Yearly
+      other: Every %{count} years
+    'on': on the %{sentence}
+    in: 'in %{target}'
+    integer:
+      negative: '%{ordinal} to last'
+      literal_ordinals:
+        -1: last
+        -2: 2nd to last
+      ordinal: '%{number}%{ordinal}'
+      ordinals:
+        default: th
+        1: st
+        2: nd
+        3: rd
+        11: th
+        12: th
+        13: th
+    on_weekends: on Weekends
+    on_weekdays: on Weekdays
+    days_on:
+      - Sundays
+      - Mondays
+      - Tuesdays
+      - Wednesdays
+      - Thursdays
+      - Fridays
+      - Saturdays
+    on_days: on %{days}
+    array:
+      last_word_connector: ', and '
+      two_words_connector: ' and '
+      words_connector: ', '
+    string:
+      format:
+        day: '%{rest} %{current}'
+        day_of_week: '%{rest} %{current}'
+        day_of_month: '%{rest} %{current}'
+        day_of_year: '%{rest} %{current}'
+        hour_of_day: '%{rest} %{current}'
+        minute_of_hour: '%{rest} %{current}'
+        until: '%{rest} %{current}'
+        count: '%{rest} %{current}'
+        default: '%{rest} %{current}'

config/locales/ja.yml

@@ -0,0 +1,107 @@
+ja:
+  ice_cube:
+    pieces_connector: ' / '
+    not: '%{target}以外'
+    not_on: '%{target}以外'
+    date:
+      formats:
+        default: '%Y年%m月%d日'
+      month_names:
+      -
+      - 1月
+      - 2月
+      - 3月
+      - 4月
+      - 5月
+      - 6月
+      - 7月
+      - 8月
+      - 9月
+      - 10月
+      - 11月
+      - 12月
+      day_names:
+      - 日曜
+      - 月曜
+      - 火曜
+      - 水曜
+      - 木曜
+      - 金曜
+      - 土曜
+    times:
+      other: '%{count}回'
+      one: '%{count}回'
+    until: '%{date}まで'
+    days_of_week: '%{segments}%{day}'
+    days_of_month:
+      other: '%{segments}日'
+      one: '%{segments}日'
+    days_of_year:
+      other: '%{segments}日'
+      one: '%{segments}日'
+    at_hours_of_the_day:
+      other: '%{segments}時'
+      one: '%{segments}時'
+    on_minutes_of_hour:
+      other: '%{segments}分'
+      one: '%{segments}分'
+    on_seconds_of_minute:
+      other: '%{segments}秒'
+      one: '%{segments}秒'
+    each_second:
+      one: 毎秒
+      other: '%{count}秒ごと'
+    each_minute:
+      one: 毎分
+      other: '%{count}分ごと'
+    each_hour:
+      one: 毎時間
+      other: '%{count}時間ごと'
+    each_day:
+      one: 毎日
+      other: '%{count}日ごと'
+    each_week:
+      one: 毎週
+      other: '%{count}週間ごと'
+    each_month:
+      one: 毎月
+      other: '%{count}ヶ月ごと'
+    each_year:
+      one: 毎年
+      other: '%{count}年ごと'
+    'on': '%{sentence}'
+    in: '%{target}'
+    integer:
+      negative: '最終%{ordinal}'
+      literal_ordinals:
+        -1: 最終
+        -2: 最後から2番目の
+      ordinal: '%{ordinal}%{number}'
+      ordinals:
+        default: ''
+    on_weekends: 週末
+    on_weekdays: 平日
+    days_on:
+      - 日曜
+      - 月曜
+      - 火曜
+      - 水曜
+      - 木曜
+      - 金曜
+      - 土曜
+    on_days: '%{days}'
+    array:
+      last_word_connector: '、'
+      two_words_connector: '、'
+      words_connector: '、'
+    string:
+      format:
+        day: '%{rest}%{current}'
+        day_of_week: '%{rest}%{current}'
+        day_of_month: '%{rest}%{current}'
+        day_of_year: '%{rest}%{current}'
+        hour_of_day: '%{rest}%{current}'
+        minute_of_hour: '%{rest}%{current}'
+        until: '%{current}%{rest}'
+        count: '%{rest}%{current}'
+        default: '%{rest}%{current}'

ice_cube.gemspec

@@ -21,4 +21,5 @@ Gem::Specification.new do |s|
   s.add_development_dependency('rspec', '~> 2.12.0')
   s.add_development_dependency('activesupport', '>= 3.0.0')
   s.add_development_dependency('tzinfo')
+  s.add_runtime_dependency('i18n')
 end

lib/ice_cube.rb

@@ -1,5 +1,8 @@
 require 'date'
 require 'ice_cube/deprecated'
+require 'i18n'
+
+I18n.load_path += Dir[File.expand_path('../../config/locales/*{rb,yml}', __FILE__)]
 
 module IceCube
 
@@ -68,7 +71,7 @@ module Validations
   # Defines the format used by IceCube when printing out Schedule#to_s.
   # Defaults to '%B %e, %Y'
   def self.to_s_time_format
-    @to_s_time_format ||= '%B %e, %Y'
+    @to_s_time_format ||= I18n.t("ice_cube.date.formats.default")
   end
 
   # Sets the format used by IceCube when printing out Schedule#to_s.

lib/ice_cube/builders/string_builder.rb

@@ -13,14 +13,18 @@ def piece(type, prefix = nil, suffix = nil)
     end
 
     def to_s
-      @types.each_with_object(@base || '') do |(type, segments), str|
+      string = @base || ''
+      @types.each do |type, segments|
         if f = self.class.formatter(type)
-          str << ' ' << f.call(segments)
+          current = f.call(segments)
         else
           next if segments.empty?
-          str << ' ' << self.class.sentence(segments)
+          current = self.class.sentence(segments)
         end
+        f = I18n.t('ice_cube.string.format')[type] ? type : 'default'
+        string = I18n.t("ice_cube.string.format.#{f}", rest: string, current: current)
       end
+      string
     end
 
     def self.formatter(type)
@@ -34,27 +38,33 @@ def self.register_formatter(type, &formatter)
 
     module Helpers
 
-      NUMBER_SUFFIX = ['th', 'st', 'nd', 'rd', 'th', 'th', 'th', 'th', 'th', 'th']
-      SPECIAL_SUFFIX = { 11 => 'th', 12 => 'th', 13 => 'th', 14 => 'th' }
-
       # influenced by ActiveSupport's to_sentence
       def sentence(array)
         case array.length
         when 0 ; ''
         when 1 ; array[0].to_s
-        when 2 ; "#{array[0]} and #{array[1]}"
-        else ; "#{array[0...-1].join(', ')}, and #{array[-1]}"
+        when 2 ; "#{array[0]}#{I18n.t('ice_cube.array.two_words_connector')}#{array[1]}"
+        else ; "#{array[0...-1].join(I18n.t('ice_cube.array.words_connector'))}#{I18n.t('ice_cube.array.last_word_connector')}#{array[-1]}"
         end
       end
 
       def nice_number(number)
-        return 'last' if number == -1
-        suffix = SPECIAL_SUFFIX[number] || NUMBER_SUFFIX[number.abs % 10]
-        if number < -1
-          number.abs.to_s << suffix << ' to last'
-        else
-          number.to_s << suffix
-        end
+        literal_ordinal(number) || ordinalize(number)
+      end
+
+      def ordinalize(number)
+        I18n.t('ice_cube.integer.ordinal', number: number, ordinal: ordinal(number))
+      end
+
+      def literal_ordinal(number)
+        I18n.t("ice_cube.integer.literal_ordinals")[number]
+      end
+
+      def ordinal(number)
+        ord = I18n.t("ice_cube.integer.ordinals")[number] ||
+          I18n.t("ice_cube.integer.ordinals")[number % 10] ||
+          I18n.t('ice_cube.integer.ordinals')[:default]
+        number >= 0 ? ord : I18n.t("ice_cube.integer.negative", ordinal: ord)
       end
 
     end

lib/ice_cube/schedule.rb

@@ -315,9 +315,11 @@ def to_s
       rd = recurrence_times_with_start_time - extimes
       pieces.concat rd.sort.map { |t| t.strftime(IceCube.to_s_time_format) }
       pieces.concat rrules.map  { |t| t.to_s }
-      pieces.concat exrules.map { |t| "not #{t.to_s}" }
-      pieces.concat extimes.sort.map { |t| "not on #{t.strftime(IceCube.to_s_time_format)}" }
-      pieces.join(' / ')
+      pieces.concat exrules.map { |t| I18n.t('ice_cube.not', target: t.to_s) }
+      pieces.concat extimes.sort.map { |t|
+        I18n.t('ice_cube.not_on', target: t.strftime(IceCube.to_s_time_format))
+      }
+      pieces.join(I18n.t('ice_cube.pieces_connector'))
     end
 
     # Serialize this schedule to_ical

lib/ice_cube/validations/count.rb

@@ -51,7 +51,7 @@ def build_ical(builder)
 
       StringBuilder.register_formatter(:count) do |segments|
         count = segments.first
-        "#{count} #{count == 1 ? 'time' : 'times'}"
+        I18n.t('ice_cube.times', count: count)
       end
 
     end

lib/ice_cube/validations/daily_interval.rb

@@ -35,7 +35,7 @@ def validate(step_time, schedule)
       end
 
       def build_s(builder)
-        builder.base = interval == 1 ? 'Daily' : "Every #{interval} days"
+        builder.base = I18n.t('ice_cube.each_day', count: interval)
       end
 
       def build_hash(builder)

lib/ice_cube/validations/day.rb

@@ -54,12 +54,13 @@ def build_ical(builder)
         validation_days.sort!
         # pick the right shortening, if applicable
         if validation_days == [0, 6]
-          'on Weekends'
+          I18n.t('ice_cube.on_weekends')
         elsif validation_days == (1..5).to_a
-          'on Weekdays'
+          I18n.t('ice_cube.on_weekdays')
         else
-          segments = validation_days.map { |d| "#{Date::DAYNAMES[d]}s" }
-          "on #{StringBuilder.sentence(segments)}"
+          day_names = ->(d){ "#{I18n.t("ice_cube.days_on")[d]}" }
+          segments = validation_days.map(&day_names)
+          I18n.t('ice_cube.on_days', days: StringBuilder.sentence(segments))
         end
       end
 

lib/ice_cube/validations/day_of_month.rb

@@ -43,9 +43,9 @@ def build_ical(builder)
       end
 
       StringBuilder.register_formatter(:day_of_month) do |entries|
-        str = "on the #{StringBuilder.sentence(entries)} "
-        str << (entries.size == 1 ? 'day of the month' : 'days of the month')
-        str
+        sentence = StringBuilder.sentence(entries)
+        str = I18n.t('ice_cube.days_of_month', count: entries.size, segments: sentence)
+        I18n.t('ice_cube.on', sentence: str)
       end
 
     end