python/rox/i18n.py

   1 """If you want your program to be translated into multiple languages you need
   2 to do the following:
   3
   4 - Pass all strings that should be translated through the '_' function, eg:
   5         print _('Hello World!')
   6
   7 - Create a Messages subdirectory in your application.
   8
   9 - Run 'pygettext *.py' to extract all the marked strings.
  10
  11 - Copy messages.pot as Messages/<lang>.po and edit (see ROX-Lib2's README).
  12
  13 - Use msgfmt to convert the .po files to .gmo files.
  14
  15 - In your application, use the rox.i18n.translation() function to set the _ function:
  16         __builtins__._ = rox.i18n.translation(os.path.join(rox.app_dir, 'Messages'))
  17   (for libraries, just do '_ ='; don't mess up the builtins)
  18
  19 Note that the marked strings must be fixed. If you're using formats, mark up the
  20 format, eg:
  21
  22         print _('You have %d lives remaining') % lives
  23
  24 You might like to look at the scripts in ROX-Lib2's Messages directory for
  25 more help.
  26 """
  27
  28 import os
  29
  30 def _expand_lang(locale):
  31         from locale import normalize
  32         locale = normalize(locale)
  33         COMPONENT_CODESET   = 1 << 0
  34         COMPONENT_TERRITORY = 1 << 1
  35         COMPONENT_MODIFIER  = 1 << 2
  36         # split up the locale into its base components
  37         mask = 0
  38         pos = locale.find('@')
  39         if pos >= 0:
  40                 modifier = locale[pos:]
  41                 locale = locale[:pos]
  42                 mask |= COMPONENT_MODIFIER
  43         else:
  44                 modifier = ''
  45         pos = locale.find('.')
  46         if pos >= 0:
  47                 codeset = locale[pos:]
  48                 locale = locale[:pos]
  49                 mask |= COMPONENT_CODESET
  50         else:
  51                 codeset = ''
  52         pos = locale.find('_')
  53         if pos >= 0:
  54                 territory = locale[pos:]
  55                 locale = locale[:pos]
  56                 mask |= COMPONENT_TERRITORY
  57         else:
  58                 territory = ''
  59         language = locale
  60         ret = []
  61         for i in range(mask+1):
  62                 if not (i & ~mask):  # if all components for this combo exist ...
  63                         val = language
  64                         if i & COMPONENT_TERRITORY: val += territory
  65                         if i & COMPONENT_CODESET:   val += codeset
  66                         if i & COMPONENT_MODIFIER:  val += modifier
  67                         ret.append(val)
  68         ret.reverse()
  69         return ret
  70
  71 def expand_languages(languages = None):
  72         # Get some reasonable defaults for arguments that were not supplied
  73         if languages is None:
  74                 languages = []
  75                 for envar in ('LANGUAGE', 'LC_ALL', 'LC_MESSAGES', 'LANG'):
  76                         val = os.environ.get(envar)
  77                         if val:
  78                                 languages = val.split(':')
  79                                 break
  80         if 'C' not in languages:
  81                 languages.append('C')
  82
  83         # now normalize and expand the languages
  84         nelangs = []
  85         for lang in languages:
  86                 for nelang in _expand_lang(lang):
  87                         if nelang not in nelangs:
  88                                 nelangs.append(nelang)
  89         return nelangs
  90
  91 # Locate a .mo file using the ROX strategy
  92 def find(messages_dir, languages = None):
  93         """Look in messages_dir for a .gmo file for the user's preferred language
  94         (or override this with the 'languages' argument). Returns the filename, or
  95         None if there was no translation."""
  96         # select a language
  97         for lang in expand_languages(languages):
  98                 if lang == 'C':
  99                         break
 100                 mofile = os.path.join(messages_dir, '%s.gmo' % lang)
 101                 if os.path.exists(mofile):
 102                         return mofile
 103         return None
 104
 105 def translation(messages_dir, languages = None):
 106         """Load the translation for the user's language and return a function
 107         which translates a string into its unicode equivalent."""
 108         mofile = find(messages_dir, languages)
 109         if not mofile:
 110                 return lambda x: x
 111         import gettext
 112         return gettext.GNUTranslations(file(mofile)).ugettext
 113
 114 langs = expand_languages()