Problems with translated strings

[capink]

Thers is a problem reported by BetterRed in regards to menu items in the Favourites Menu plugin. The problem is that when a user switches to a different language, the menu item text is changed to a translated string in that language, and the Favourites Menu plugin cannot find the menu item because it relies on it having the same name.

This problem would also affect the action chains plugin as it shares code with the Favourites Menu plugin. I was able to solve the problem, but only partially by using this:

paths = [paths[0]] + [_(x) for x in paths[1:]]

This only solves the problem if the user configures the Favourites Menu plugin in English and switches to another language. However, it does not help with the reverse situation when a user configures the plugin in a language other than English and then switches languages.

The solution to this, would be to get the original English untranslated string (msgid) from the translated string (msgstr), and persist the msgid in the json file instead of the msgstr. I don't know how to get the msgid from the msgstr. Is this possible? Can someone help with this or any other alternative solutions?

[kovidgoyal]

well gettext doesnt have a way to do reverse lookups, but the gettext database format is pretty trivial so you should be able to write your own. You could use the source code of the msgunfmt utility as a starting point. You can fin the .mo files in resources/localization/locales.zip in a calibre install folder. And this is the file spec: https://www.gnu.org/software/gettext.../MO-Files.html

[kovidgoyal]

Actually its a lot easier than that.

def reverse_lookup(translated_string):
    if not hasattr(reverse_lookup, 'cache'):
         reverse_lookup.cache = {v: k for k, v _.__self__._catalog.items()}
    return reverse_lookup.cache.get(translated_string)

[capink]

Thanks for the reply. I tried the above but I'm getting this error:

AttributeError: 'NullTranslations' object has no attribute '_catalog'

My knowledge of gettext and translation is very limited. I tried to look for ways to correctly get the catalog object but I failed. The python gettext docs did not offer much help for me.

[kovidgoyal]

That's when there are no translations installed (english). Here you go:

def reverse_lookup(translated_string):
    if not hasattr(_.__self__, '_catalog'):
         return translated_string
    if not hasattr(reverse_lookup, 'cache'):
         reverse_lookup.cache = {v: k for k, v _.__self__._catalog.items()}
    ans = reverse_lookup.cache.get(translated_string, translated_string)
    if isinstance(ans, tuple):
          ans  = ans[1]
    return

this handles no translations and also plural forms. And yes the docs of gettext are useless for this, read the source of the gettext.py module instead, its pretty simple.

[capink]

Thank you very much. It is working now.