Troubles with python internationalization

[Pascal Chambon]

Hello

I'm studying the migration of my website (mixed english and french
languages...) to a properly localized architecture.

From what I've read so far, using translation "tags" (or quick phrases)
in the code, and translating them to every target language (including
english) sounds a better approach than using, for example, final english
wordings as translation tags. The setup is longer via the first way, but
at least if you change english wordings later, you don't break all other
translations at the same time.

However, I still have problems with some aspects of internationalization:

* code safety : it seems default python string formatting technics (%
operator, .format() method) are normally used when one needs to
substitute placeholders in translated strings. But the thing is : I DONT
want my view to raise an exception simply because one of the
translations has forgotten a damn "%(myvar)s" placeholder. The only
quick fix I can think of, is to always use substitution through
defaultdicts instances (and still, exceptions could occur if abnormal
"%s" placeholders are found in the translated string).
Are there some utilities in python, or frameworks like django,
to allow a safe string substitution (which might,
for example, simply log an error if a buggy string si found) ? Python's
template strings' "safe_substitute()" won't fit, because it swallows
errors without any notice...

* unknown translatable strings : I have in different data files (eg.
yaml), strings which will need translation, but that can't be detected
by gettext and co, since they only appear in the code as variable i.e
"_(yamlvar)". The easiest, I guess, would be to replace them by specific
tags (like "TR_HOMEPAGE_TITLE"), and to have a tool browse the code to
extract them and add them to the standard gettext translation chain.
Such a tool shouldn't be too hard to code, but I'd rather know : doesn't
such a tool already exist somewhere ? I've seen no such mention in
gettext or babel tools, only recogniztion via function calls ( _(),
tr()... ).

* I have seen nowhere mention of how to remove deprecated/unused strings
from gettext files - only merging translations seems to interest people.
However, having a translation file which slowly fills itself with
outdated data doesn't sound cool to me. Does anyone know tools/program
flags which would list/extract translations that don't seem used anymore ?


Thanks for you help,

regards,
Pascal

 

[Dan Stromberg]

* code safety : it seems default python string formatting technics (%
operator, .format() method) are normally used when one needs to
substitute placeholders in translated strings. But the thing is : I DONT
want my view to raise an exception simply because one of the
translations has forgotten a damn "%(myvar)s" placeholder. The only
quick fix I can think of, is to always use substitution through
defaultdicts instances (and still, exceptions could occur if abnormal
"%s" placeholders are found in the translated string).
Are there some utilities in python, or frameworks like django,
  to allow a safe string substitution (which might,
for example, simply log an error if a buggy string si found)  ? Python's
template strings' "safe_substitute()" won't fit, because it swallows
errors without any notice...

For this one, you might check into pylint. I've just recently started
using it, but I'm loving it. I pretty much don't check things in
without first running them through pylint (and some unit tests) first
now.