Add extern/i18n.lua

9 files changed, 782 insertions, 0 deletions

diff --git a/extern/i18n.lua/CMakeLists.txt b/extern/i18n.lua/CMakeLists.txt
new file mode 100644
index 0000000000..aec4447470
--- /dev/null
+++ b/extern/i18n.lua/CMakeLists.txt
@@ -0,0 +1,17 @@
+if (NOT DEFINED OPENMW_RESOURCES_ROOT)
+    message( FATAL_ERROR "OPENMW_RESOURCES_ROOT is not set" )
+endif()
+
+# Copy resource files into the build directory
+set(SDIR ${CMAKE_CURRENT_SOURCE_DIR})
+set(DDIRRELATIVE resources/lua_libs/i18n)
+
+set(I18N_LUA_FILES
+    i18n/init.lua
+    i18n/interpolate.lua
+    i18n/plural.lua
+    i18n/variants.lua
+    i18n/version.lua
+)
+
+copy_all_resource_files(${CMAKE_CURRENT_SOURCE_DIR} ${OPENMW_RESOURCES_ROOT} ${DDIRRELATIVE} "${I18N_LUA_FILES}")
diff --git a/extern/i18n.lua/LICENSE b/extern/i18n.lua/LICENSE
new file mode 100644
index 0000000000..ddf484685b
--- /dev/null
+++ b/extern/i18n.lua/LICENSE
@@ -0,0 +1,22 @@
+MIT License Terms
+=================
+
+Copyright (c) 2012 Enrique García Cota.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/extern/i18n.lua/README.md b/extern/i18n.lua/README.md
new file mode 100644
index 0000000000..8b3271c321
--- /dev/null
+++ b/extern/i18n.lua/README.md
@@ -0,0 +1,164 @@
+i18n.lua
+========
+
+[![Build Status](https://travis-ci.org/kikito/i18n.lua.png?branch=master)](https://travis-ci.org/kikito/i18n.lua)
+
+A very complete i18n lib for Lua
+
+Description
+===========
+
+``` lua
+i18n = require 'i18n'
+
+-- loading stuff
+i18n.set('en.welcome', 'welcome to this program')
+i18n.load({
+  en = {
+    good_bye = "good-bye!",
+    age_msg = "your age is %{age}.",
+    phone_msg = {
+      one = "you have one new message.",
+      other = "you have %{count} new messages."
+    }
+  }
+})
+i18n.loadFile('path/to/your/project/i18n/de.lua') -- load German language file
+i18n.loadFile('path/to/your/project/i18n/fr.lua') -- load French language file
+…         -- section 'using language files' below describes structure of files
+
+-- setting the translation context
+i18n.setLocale('en') -- English is the default locale anyway
+
+-- getting translations
+i18n.translate('welcome') -- Welcome to this program
+i18n('welcome') -- Welcome to this program
+i18n('age_msg', {age = 18}) -- Your age is 18.
+i18n('phone_msg', {count = 1}) -- You have one new message.
+i18n('phone_msg', {count = 2}) -- You have 2 new messages.
+i18n('good_bye') -- Good-bye!
+
+```
+
+Interpolation
+=============
+
+You can interpolate variables in 3 different ways:
+
+``` lua
+-- the most usual one
+i18n.set('variables', 'Interpolating variables: %{name} %{age}')
+i18n('variables', {name='john', 'age'=10}) -- Interpolating variables: john 10
+
+i18n.set('lua', 'Traditional Lua way: %d %s')
+i18n('lua', {1, 'message'}) -- Traditional Lua way: 1 message
+
+i18n.set('combined', 'Combined: %<name>.q %<age>.d %<age>.o')
+i18n('combined', {name='john', 'age'=10}) -- Combined: john 10 12k
+```
+
+
+
+Pluralization
+=============
+
+This lib implements the [unicode.org plural rules](http://cldr.unicode.org/index/cldr-spec/plural-rules). Just set the locale you want to use and it will deduce the appropiate pluralization rules:
+
+``` lua
+i18n = require 'i18n'
+
+i18n.load({
+  en = {
+    msg = {
+      one   = "one message",
+      other = "%{count} messages"
+    }
+  },
+  ru = {
+    msg = {
+      one   = "1 сообщение",
+      few   = "%{count} сообщения",
+      many  = "%{count} сообщений",
+      other = "%{count} сообщения"
+    }
+  }
+})
+
+i18n('msg', {count = 1}) -- one message
+i18n.setLocale('ru')
+i18n('msg', {count = 5}) -- 5 сообщений
+```
+
+The appropiate rule is chosen by finding the 'root' of the locale used: for example if the current locale is 'fr-CA', the 'fr' rules will be applied.
+
+If the provided functions are not enough (i.e. invented languages) it's possible to specify a custom pluralization function in the second parameter of setLocale. This function must return 'one', 'few', 'other', etc given a number.
+
+Fallbacks
+=========
+
+When a value is not found, the lib has several fallback mechanisms:
+
+* First, it will look in the current locale's parents. For example, if the locale was set to 'en-US' and the key 'msg' was not found there, it will be looked over in 'en'.
+* Second, if the value is not found in the locale ancestry, a 'fallback locale' (by default: 'en') can be used. If the fallback locale has any parents, they will be looked over too.
+* Third, if all the locales have failed, but there is a param called 'default' on the provided data, it will be used.
+* Otherwise the translation will return nil.
+
+The parents of a locale are found by splitting the locale by its hyphens. Other separation characters (spaces, underscores, etc) are not supported.
+
+Using language files
+====================
+
+It might be a good idea to store each translation in a different file. This is supported via the 'i18n.loadFile' directive:
+
+``` lua
+…
+i18n.loadFile('path/to/your/project/i18n/de.lua') -- German translation
+i18n.loadFile('path/to/your/project/i18n/en.lua') -- English translation
+i18n.loadFile('path/to/your/project/i18n/fr.lua') -- French translation
+…
+```
+
+The German language file 'de.lua' should read:
+
+``` lua
+return {
+  de = {
+    good_bye = "Auf Wiedersehen!",
+    age_msg = "Ihr Alter beträgt %{age}.",
+    phone_msg = {
+      one = "Sie haben eine neue Nachricht.",
+      other = "Sie haben %{count} neue Nachrichten."
+    }
+  }
+}
+```
+
+If desired, you can also store all translations in one single file (eg. 'translations.lua'):
+
+``` lua
+return {
+  de = {
+    good_bye = "Auf Wiedersehen!",
+    age_msg = "Ihr Alter beträgt %{age}.",
+    phone_msg = {
+      one = "Sie haben eine neue Nachricht.",
+      other = "Sie haben %{count} neue Nachrichten."
+    }
+  },
+  fr = {
+    good_bye = "Au revoir !",
+    age_msg = "Vous avez %{age} ans.",
+    phone_msg = {
+      one = "Vous avez une noveau message.",
+      other = "Vous avez %{count} noveaux messages."
+    }
+  },
+  …
+}
+```
+
+Specs
+=====
+This project uses [busted](https://github.com/Olivine-Labs/busted) for its specs. If you want to run the specs, you will have to install it first. Then just execute the following from the root inspect folder:
+
+    busted
diff --git a/extern/i18n.lua/i18n/init.lua b/extern/i18n.lua/i18n/init.lua
new file mode 100644
index 0000000000..6bcccd0572
--- /dev/null
+++ b/extern/i18n.lua/i18n/init.lua
@@ -0,0 +1,188 @@
+local i18n = {}
+
+local store
+local locale
+local pluralizeFunction
+local defaultLocale = 'en'
+local fallbackLocale = defaultLocale
+
+local currentFilePath = (...):gsub("%.init$","")
+
+local plural      = require(currentFilePath .. '.plural')
+local interpolate = require(currentFilePath .. '.interpolate')
+local variants    = require(currentFilePath .. '.variants')
+local version     = require(currentFilePath .. '.version')
+
+i18n.plural, i18n.interpolate, i18n.variants, i18n.version, i18n._VERSION =
+  plural, interpolate, variants, version, version
+
+-- private stuff
+
+local function dotSplit(str)
+  local fields, length = {},0
+    str:gsub("[^%.]+", function(c)
+    length = length + 1
+    fields[length] = c
+  end)
+  return fields, length
+end
+
+local function isPluralTable(t)
+  return type(t) == 'table' and type(t.other) == 'string'
+end
+
+local function isPresent(str)
+  return type(str) == 'string' and #str > 0
+end
+
+local function assertPresent(functionName, paramName, value)
+  if isPresent(value) then return end
+
+  local msg = "i18n.%s requires a non-empty string on its %s. Got %s (a %s value)."
+  error(msg:format(functionName, paramName, tostring(value), type(value)))
+end
+
+local function assertPresentOrPlural(functionName, paramName, value)
+  if isPresent(value) or isPluralTable(value) then return end
+
+  local msg = "i18n.%s requires a non-empty string or plural-form table on its %s. Got %s (a %s value)."
+  error(msg:format(functionName, paramName, tostring(value), type(value)))
+end
+
+local function assertPresentOrTable(functionName, paramName, value)
+  if isPresent(value) or type(value) == 'table' then return end
+
+  local msg = "i18n.%s requires a non-empty string or table on its %s. Got %s (a %s value)."
+  error(msg:format(functionName, paramName, tostring(value), type(value)))
+end
+
+local function assertFunctionOrNil(functionName, paramName, value)
+  if value == nil or type(value) == 'function' then return end
+
+  local msg = "i18n.%s requires a function (or nil) on param %s. Got %s (a %s value)."
+  error(msg:format(functionName, paramName, tostring(value), type(value)))
+end
+
+local function defaultPluralizeFunction(count)
+  return plural.get(variants.root(i18n.getLocale()), count)
+end
+
+local function pluralize(t, data)
+  assertPresentOrPlural('interpolatePluralTable', 't', t)
+  data = data or {}
+  local count = data.count or 1
+  local plural_form = pluralizeFunction(count)
+  return t[plural_form]
+end
+
+local function treatNode(node, data)
+  if type(node) == 'string' then
+    return interpolate(node, data)
+  elseif isPluralTable(node) then
+    return interpolate(pluralize(node, data), data)
+  end
+  return node
+end
+
+local function recursiveLoad(currentContext, data)
+  local composedKey
+  for k,v in pairs(data) do
+    composedKey = (currentContext and (currentContext .. '.') or "") .. tostring(k)
+    assertPresent('load', composedKey, k)
+    assertPresentOrTable('load', composedKey, v)
+    if type(v) == 'string' then
+      i18n.set(composedKey, v)
+    else
+      recursiveLoad(composedKey, v)
+    end
+  end
+end
+
+local function localizedTranslate(key, loc, data)
+  local path, length = dotSplit(loc .. "." .. key)
+  local node = store
+
+  for i=1, length do
+    node = node[path[i]]
+    if not node then return nil end
+  end
+
+  return treatNode(node, data)
+end
+
+-- public interface
+
+function i18n.set(key, value)
+  assertPresent('set', 'key', key)
+  assertPresentOrPlural('set', 'value', value)
+
+  local path, length = dotSplit(key)
+  local node = store
+
+  for i=1, length-1 do
+    key = path[i]
+    node[key] = node[key] or {}
+    node = node[key]
+  end
+
+  local lastKey = path[length]
+  node[lastKey] = value
+end
+
+function i18n.translate(key, data)
+  assertPresent('translate', 'key', key)
+
+  data = data or {}
+  local usedLocale = data.locale or locale
+
+  local fallbacks = variants.fallbacks(usedLocale, fallbackLocale)
+  for i=1, #fallbacks do
+    local value = localizedTranslate(key, fallbacks[i], data)
+    if value then return value end
+  end
+
+  return data.default
+end
+
+function i18n.setLocale(newLocale, newPluralizeFunction)
+  assertPresent('setLocale', 'newLocale', newLocale)
+  assertFunctionOrNil('setLocale', 'newPluralizeFunction', newPluralizeFunction)
+  locale = newLocale
+  pluralizeFunction = newPluralizeFunction or defaultPluralizeFunction
+end
+
+function i18n.setFallbackLocale(newFallbackLocale)
+  assertPresent('setFallbackLocale', 'newFallbackLocale', newFallbackLocale)
+  fallbackLocale = newFallbackLocale
+end
+
+function i18n.getFallbackLocale()
+  return fallbackLocale
+end
+
+function i18n.getLocale()
+  return locale
+end
+
+function i18n.reset()
+  store = {}
+  plural.reset()
+  i18n.setLocale(defaultLocale)
+  i18n.setFallbackLocale(defaultLocale)
+end
+
+function i18n.load(data)
+  recursiveLoad(nil, data)
+end
+
+function i18n.loadFile(path)
+  local chunk = assert(loadfile(path))
+  local data = chunk()
+  i18n.load(data)
+end
+
+setmetatable(i18n, {__call = function(_, ...) return i18n.translate(...) end})
+
+i18n.reset()
+
+return i18n
diff --git a/extern/i18n.lua/i18n/interpolate.lua b/extern/i18n.lua/i18n/interpolate.lua
new file mode 100644
index 0000000000..c6bb242f05
--- /dev/null
+++ b/extern/i18n.lua/i18n/interpolate.lua
@@ -0,0 +1,60 @@
+local unpack = unpack or table.unpack -- lua 5.2 compat
+
+local FORMAT_CHARS = { c=1, d=1, E=1, e=1, f=1, g=1, G=1, i=1, o=1, u=1, X=1, x=1, s=1, q=1, ['%']=1 }
+
+-- matches a string of type %{age}
+local function interpolateValue(string, variables)
+  return string:gsub("(.?)%%{%s*(.-)%s*}",
+    function (previous, key)
+      if previous == "%" then
+        return
+      else
+        return previous .. tostring(variables[key])
+      end
+    end)
+end
+
+-- matches a string of type %<age>.d
+local function interpolateField(string, variables)
+  return string:gsub("(.?)%%<%s*(.-)%s*>%.([cdEefgGiouXxsq])",
+    function (previous, key, format)
+      if previous == "%" then
+        return
+      else
+        return previous .. string.format("%" .. format, variables[key] or "nil")
+      end
+    end)
+end
+
+local function escapePercentages(string)
+  return string:gsub("(%%)(.?)", function(_, char)
+    if FORMAT_CHARS[char] then
+      return "%" .. char
+    else
+      return "%%" .. char
+    end
+  end)
+end
+
+local function unescapePercentages(string)
+  return string:gsub("(%%%%)(.?)", function(_, char)
+    if FORMAT_CHARS[char] then
+      return "%" .. char
+    else
+      return "%%" .. char
+    end
+  end)
+end
+
+local function interpolate(pattern, variables)
+  variables = variables or {}
+  local result = pattern
+  result = interpolateValue(result, variables)
+  result = interpolateField(result, variables)
+  result = escapePercentages(result)
+  result = string.format(result, unpack(variables))
+  result = unescapePercentages(result)
+  return result
+end
+
+return interpolate
diff --git a/extern/i18n.lua/i18n/plural.lua b/extern/i18n.lua/i18n/plural.lua
new file mode 100644
index 0000000000..bb99804ee8
--- /dev/null
+++ b/extern/i18n.lua/i18n/plural.lua
@@ -0,0 +1,280 @@
+local plural = {}
+local defaultFunction = nil
+-- helper functions
+
+local function assertPresentString(functionName, paramName, value)
+  if type(value) ~= 'string' or #value == 0 then
+    local msg = "Expected param %s of function %s to be a string, but got %s (a value of type %s) instead"
+    error(msg:format(paramName, functionName, tostring(value), type(value)))
+  end
+end
+
+local function assertNumber(functionName, paramName, value)
+  if type(value) ~= 'number' then
+    local msg = "Expected param %s of function %s to be a number, but got %s (a value of type %s) instead"
+    error(msg:format(paramName, functionName, tostring(value), type(value)))
+  end
+end
+
+-- transforms "foo bar baz" into {'foo','bar','baz'}
+local function words(str)
+  local result, length = {}, 0
+  str:gsub("%S+", function(word)
+    length = length + 1
+    result[length] = word
+  end)
+  return result
+end
+
+local function isInteger(n)
+  return n == math.floor(n)
+end
+
+local function between(value, min, max)
+  return value >= min and value <= max
+end
+
+local function inside(v, list)
+  for i=1, #list do
+    if v == list[i] then return true end
+  end
+  return false
+end
+
+
+-- pluralization functions
+
+local pluralization = {}
+
+local f1 = function(n)
+  return n == 1 and "one" or "other"
+end
+pluralization[f1] = words([[
+  af asa bem bez bg bn brx ca cgg chr da de dv ee el
+  en eo es et eu fi fo fur fy gl gsw gu ha haw he is
+  it jmc kaj kcg kk kl ksb ku lb lg mas ml mn mr nah
+  nb nd ne nl nn no nr ny nyn om or pa pap ps pt rm
+  rof rwk saq seh sn so sq ss ssy st sv sw syr ta te
+  teo tig tk tn ts ur ve vun wae xh xog zu
+]])
+
+local f2 = function(n)
+  return (n == 0 or n == 1) and "one" or "other"
+end
+pluralization[f2] = words("ak am bh fil guw hi ln mg nso ti tl wa")
+
+local f3 = function(n)
+  if not isInteger(n) then return 'other' end
+  return (n == 0 and "zero") or
+         (n == 1 and "one") or
+         (n == 2 and "two") or
+         (between(n % 100, 3, 10) and "few") or
+         (between(n % 100, 11, 99) and "many") or
+         "other"
+end
+pluralization[f3] = {'ar'}
+
+local f4 = function()
+  return "other"
+end
+pluralization[f4] = words([[
+  az bm bo dz fa hu id ig ii ja jv ka kde kea km kn
+  ko lo ms my root sah ses sg th to tr vi wo yo zh
+]])
+
+local f5 = function(n)
+  if not isInteger(n) then return 'other' end
+  local n_10, n_100 = n % 10, n % 100
+  return (n_10 == 1 and n_100 ~= 11 and 'one') or
+         (between(n_10, 2, 4) and not between(n_100, 12, 14) and 'few') or
+         ((n_10 == 0 or between(n_10, 5, 9) or between(n_100, 11, 14)) and 'many') or
+         'other'
+end
+pluralization[f5] = words('be bs hr ru sh sr uk')
+
+local f6 = function(n)
+  if not isInteger(n) then return 'other' end
+  local n_10, n_100 = n % 10, n % 100
+  return (n_10 == 1 and not inside(n_100, {11,71,91}) and 'one') or
+         (n_10 == 2 and not inside(n_100, {12,72,92}) and 'two') or
+         (inside(n_10, {3,4,9}) and
+          not between(n_100, 10, 19) and
+          not between(n_100, 70, 79) and
+          not between(n_100, 90, 99)
+          and 'few') or
+         (n ~= 0 and n % 1000000 == 0 and 'many') or
+         'other'
+end
+pluralization[f6] = {'br'}
+
+local f7 = function(n)
+  return (n == 1 and 'one') or
+         ((n == 2 or n == 3 or n == 4) and 'few') or
+         'other'
+end
+pluralization[f7] = {'cz', 'sk'}
+
+local f8 = function(n)
+  return (n == 0 and 'zero') or
+         (n == 1 and 'one') or
+         (n == 2 and 'two') or
+         (n == 3 and 'few') or
+         (n == 6 and 'many') or
+         'other'
+end
+pluralization[f8] = {'cy'}
+
+local f9 = function(n)
+  return (n >= 0 and n < 2 and 'one') or
+         'other'
+end
+pluralization[f9] = {'ff', 'fr', 'kab'}
+
+local f10 = function(n)
+  return (n == 1 and 'one') or
+         (n == 2 and 'two') or
+         ((n == 3 or n == 4 or n == 5 or n == 6) and 'few') or
+         ((n == 7 or n == 8 or n == 9 or n == 10) and 'many') or
+         'other'
+end
+pluralization[f10] = {'ga'}
+
+local f11 = function(n)
+  return ((n == 1 or n == 11) and 'one') or
+         ((n == 2 or n == 12) and 'two') or
+         (isInteger(n) and (between(n, 3, 10) or between(n, 13, 19)) and 'few') or
+         'other'
+end
+pluralization[f11] = {'gd'}
+
+local f12 = function(n)
+  local n_10 = n % 10
+  return ((n_10 == 1 or n_10 == 2 or n % 20 == 0) and 'one') or
+         'other'
+end
+pluralization[f12] = {'gv'}
+
+local f13 = function(n)
+  return (n == 1 and 'one') or
+         (n == 2 and 'two') or
+         'other'
+end
+pluralization[f13] = words('iu kw naq se sma smi smj smn sms')
+
+local f14 = function(n)
+  return (n == 0 and 'zero') or
+         (n == 1 and 'one') or
+         'other'
+end
+pluralization[f14] = {'ksh'}
+
+local f15 = function(n)
+  return (n == 0 and 'zero') or
+         (n > 0 and n < 2 and 'one') or
+         'other'
+end
+pluralization[f15] = {'lag'}
+
+local f16 = function(n)
+  if not isInteger(n) then return 'other' end
+  if between(n % 100, 11, 19) then return 'other' end
+  local n_10 = n % 10
+  return (n_10 == 1 and 'one') or
+         (between(n_10, 2, 9) and 'few') or
+         'other'
+end
+pluralization[f16] = {'lt'}
+
+local f17 = function(n)
+  return (n == 0 and 'zero') or
+         ((n % 10 == 1 and n % 100 ~= 11) and 'one') or
+         'other'
+end
+pluralization[f17] = {'lv'}
+
+local f18 = function(n)
+  return((n % 10 == 1 and n ~= 11) and 'one') or
+         'other'
+end
+pluralization[f18] = {'mk'}
+
+local f19 = function(n)
+  return (n == 1 and 'one') or
+         ((n == 0 or
+          (n ~= 1 and isInteger(n) and between(n % 100, 1, 19)))
+          and 'few') or
+         'other'
+end
+pluralization[f19] = {'mo', 'ro'}
+
+local f20 = function(n)
+  if n == 1 then return 'one' end
+  if not isInteger(n) then return 'other' end
+  local n_100 = n % 100
+  return ((n == 0 or between(n_100, 2, 10)) and 'few') or
+         (between(n_100, 11, 19) and 'many') or
+         'other'
+end
+pluralization[f20] = {'mt'}
+
+local f21 = function(n)
+  if n == 1 then return 'one' end
+  if not isInteger(n) then return 'other' end
+  local n_10, n_100 = n % 10, n % 100
+
+  return ((between(n_10, 2, 4) and not between(n_100, 12, 14)) and 'few') or
+         ((n_10 == 0 or n_10 == 1 or between(n_10, 5, 9) or between(n_100, 12, 14)) and 'many') or
+         'other'
+end
+pluralization[f21] = {'pl'}
+
+local f22 = function(n)
+  return (n == 0 or n == 1) and 'one' or
+         'other'
+end
+pluralization[f22] = {'shi'}
+
+local f23 = function(n)
+  local n_100 = n % 100
+  return (n_100 == 1 and 'one') or
+         (n_100 == 2 and 'two') or
+         ((n_100 == 3 or n_100 == 4) and 'few') or
+         'other'
+end
+pluralization[f23] = {'sl'}
+
+local f24 = function(n)
+  return (isInteger(n) and (n == 0 or n == 1 or between(n, 11, 99)) and 'one')
+         or 'other'
+end
+pluralization[f24] = {'tzm'}
+
+local pluralizationFunctions = {}
+for f,locales in pairs(pluralization) do
+  for _,locale in ipairs(locales) do
+    pluralizationFunctions[locale] = f
+  end
+end
+
+-- public interface
+
+function plural.get(locale, n)
+  assertPresentString('i18n.plural.get', 'locale', locale)
+  assertNumber('i18n.plural.get', 'n', n)
+
+  local f = pluralizationFunctions[locale] or defaultFunction
+
+  return f(math.abs(n))
+end
+
+function plural.setDefaultFunction(f)
+  defaultFunction = f
+end
+
+function plural.reset()
+  defaultFunction = pluralizationFunctions['en']
+end
+
+plural.reset()
+
+return plural
diff --git a/extern/i18n.lua/i18n/variants.lua b/extern/i18n.lua/i18n/variants.lua
new file mode 100644
index 0000000000..0cfad42f6c
--- /dev/null
+++ b/extern/i18n.lua/i18n/variants.lua
@@ -0,0 +1,49 @@
+local variants = {}
+
+local function reverse(arr, length)
+  local result = {}
+  for i=1, length do result[i] = arr[length-i+1] end
+  return result, length
+end
+
+local function concat(arr1, len1, arr2, len2)
+  for i = 1, len2 do
+    arr1[len1 + i] = arr2[i]
+  end
+  return arr1, len1 + len2
+end
+
+function variants.ancestry(locale)
+  local result, length, accum = {},0,nil
+  locale:gsub("[^%-]+", function(c)
+    length = length + 1
+    accum = accum and (accum .. '-' .. c) or c
+    result[length] = accum
+  end)
+  return reverse(result, length)
+end
+
+function variants.isParent(parent, child)
+  return not not child:match("^".. parent .. "%-")
+end
+
+function variants.root(locale)
+  return locale:match("[^%-]+")
+end
+
+function variants.fallbacks(locale, fallbackLocale)
+  if locale == fallbackLocale or
+     variants.isParent(fallbackLocale, locale) then
+     return variants.ancestry(locale)
+  end
+  if variants.isParent(locale, fallbackLocale) then
+    return variants.ancestry(fallbackLocale)
+  end
+
+  local ancestry1, length1 = variants.ancestry(locale)
+  local ancestry2, length2 = variants.ancestry(fallbackLocale)
+
+  return concat(ancestry1, length1, ancestry2, length2)
+end
+
+return variants
diff --git a/extern/i18n.lua/i18n/version.lua b/extern/i18n.lua/i18n/version.lua
new file mode 100644
index 0000000000..eb788884ac
--- /dev/null
+++ b/extern/i18n.lua/i18n/version.lua
@@ -0,0 +1 @@
+return '0.9.2'
diff --git a/files/CMakeLists.txt b/files/CMakeLists.txt
index cea33f0f40..607ddeca49 100644
--- a/files/CMakeLists.txt
+++ b/files/CMakeLists.txt
@@ -3,3 +3,4 @@ add_subdirectory(shaders)
 add_subdirectory(vfs)
 add_subdirectory(builtin_scripts)
 add_subdirectory(lua_api)
+add_subdirectory(../extern/i18n.lua ${CMAKE_CURRENT_BINARY_DIR}/files)