argparse localization support

[Peter Otten]

Kwpolska wrote:

> I am using argparse in my project.  I want to localize it, but it
> seems to be impossible to change some things.  See this, for example:
> 
> usage: trash [-h] [-V] [-e] [-l] [-r] [-v] [-w] [PLIK [PLIK ...]]
> 
> Trashman — menedżer śmietnika XDG w Pythonie.
> 
> positional arguments:
>   PLIK                  pliki do wyrzucenia
> 
> optional arguments:
>   -h, --help            show this help message and exit
>   -V, --version         show program's version number and exit
> 
> (a snippet of help for Trashman, a Python trash manager, with
> LANG='pl_PL.UTF-8'; https://github.com/Kwpolska/trashman )
> 
> Anyways, you can see that -h and -V (added semi-automatically by
> argparse), “usage:” and “positional/optional arguments:” are still in
> English.  It doesn’t look very professional.  Also, I want to use
> fancy UTF-8 characters.  Is there a way to fix that?

I don't know much about gettext, but the following suggests that most 
strings in argparse are properly wrapped:

$ cat localize_argparse.py
import gettext

def my_gettext(s):
    return s.upper()
gettext.gettext = my_gettext

import argparse

if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument("-V", action="version")
    args = parser.parse_args()
$ python localize_argparse.py -h
USAGE: localize_argparse.py [-h] [-V]

OPTIONAL ARGUMENTS:
  -h, --help  SHOW THIS HELP MESSAGE AND EXIT
  -V          show program's version number and exit

The workaround for the "-V" option would be to add the help message 
explicitly

parser.add_argument("-V", ..., help=_("show..."))

You still have to provide all translations yourself.