libs/web/luasrc/i18n.lua

   1 --[[
   2 LuCI - Internationalisation
   3
   4 Description:
   5 A very minimalistic but yet effective internationalisation module
   6
   7 FileId:
   8 $Id$
   9
  10 License:
  11 Copyright 2008 Steven Barth <steven@midlink.org>
  12
  13 Licensed under the Apache License, Version 2.0 (the "License");
  14 you may not use this file except in compliance with the License.
  15 You may obtain a copy of the License at
  16
  17         http://www.apache.org/licenses/LICENSE-2.0
  18
  19 Unless required by applicable law or agreed to in writing, software
  20 distributed under the License is distributed on an "AS IS" BASIS,
  21 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  22 See the License for the specific language governing permissions and
  23 limitations under the License.
  24
  25 ]]--
  26
  27 --- LuCI translation library.
  28 module("luci.i18n", package.seeall)
  29 require("luci.util")
  30 require("lmo")
  31
  32 table   = {}
  33 i18ndir = luci.util.libpath() .. "/i18n/"
  34 loaded  = {}
  35 context = luci.util.threadlocal()
  36 default = "en"
  37
  38 --- Clear the translation table.
  39 function clear()
  40         table = {}
  41 end
  42
  43 --- Load a translation and copy its data into the translation table.
  44 -- @param file  Language file
  45 -- @param lang  Two-letter language code
  46 -- @param force Force reload even if already loaded (optional)
  47 -- @return              Success status
  48 function load(file, lang, force)
  49         lang = lang and lang:gsub("_", "-") or ""
  50         if force or not loaded[lang] or not loaded[lang][file] then
  51                 local f = lmo.open(i18ndir .. file .. "." .. lang .. ".lmo")
  52                 if f then
  53                         if not table[lang] then
  54                                 table[lang] = { f }
  55                                 setmetatable(table[lang], {
  56                                         __index = function(tbl, key)
  57                                                 for i = 1, #tbl do
  58                                                         local s = rawget(tbl, i):lookup(key)
  59                                                         if s then return s end
  60                                                 end
  61                                         end
  62                                 })
  63                         else
  64                                 table[lang][#table[lang]+1] = f
  65                         end
  66
  67                         loaded[lang] = loaded[lang] or {}
  68                         loaded[lang][file] = true
  69                         return true
  70                 else
  71                         return false
  72                 end
  73         else
  74                 return true
  75         end
  76 end
  77
  78 --- Load a translation file using the default translation language.
  79 -- Alternatively load the translation of the fallback language.
  80 -- @param file  Language file
  81 -- @param force Force reload even if already loaded (optional)
  82 function loadc(file, force)
  83         load(file, default, force)
  84         if context.parent then load(file, context.parent, force) end
  85         return load(file, context.lang, force)
  86 end
  87
  88 --- Set the context default translation language.
  89 -- @param lang  Two-letter language code
  90 function setlanguage(lang)
  91         context.lang   = lang:gsub("_", "-")
  92         context.parent = (context.lang:match("^([a-z][a-z])_"))
  93 end
  94
  95 --- Return the translated value for a specific translation key.
  96 -- @param key   Default translation text
  97 -- @return              Translated string
  98 function translate(key)
  99         return (table[context.lang] and table[context.lang][key])
 100                 or (table[context.parent] and table[context.parent][key])
 101                 or (table[default] and table[default][key])
 102                 or key
 103 end
 104
 105 --- Return the translated value for a specific translation key and use it as sprintf pattern.
 106 -- @param key           Default translation text
 107 -- @param ...           Format parameters
 108 -- @return                      Translated and formatted string
 109 function translatef(key, ...)
 110         return tostring(translate(key)):format(...)
 111 end
 112
 113 --- Return the translated value for a specific translation key
 114 -- and ensure that the returned value is a Lua string value.
 115 -- This is the same as calling <code>tostring(translate(...))</code>
 116 -- @param key           Default translation text
 117 -- @return                      Translated string
 118 function string(key)
 119         return tostring(translate(key))
 120 end
 121
 122 --- Return the translated value for a specific translation key and use it as sprintf pattern.
 123 -- Ensure that the returned value is a Lua string value.
 124 -- This is the same as calling <code>tostring(translatef(...))</code>
 125 -- @param key           Default translation text
 126 -- @param ...           Format parameters
 127 -- @return                      Translated and formatted string
 128 function stringf(key, ...)
 129         return tostring(translate(key)):format(...)
 130 end