problem mixing gettext and properties

[Peter Otten]

André wrote:

> I've encountered a problem using gettext with properties while using a
> Python interpreter.
> 
> Here's a simple program that illustrate the problem.
> ==============
> # i18n_test.py: test of gettext & properties
> 
> import gettext
> 
> fr = gettext.translation('i18n_test', './translations',
> languages=['fr'])

_ = fr.gettext # untested

> help = _("Help me!")
> 
> class Test_i18n(object):
>     def get(self):
>         __help = _("HELP!")
>         return __help
>     help_prop = property(get, None, None, 'help')
> 
> test = Test_i18n()
> 
> print help
> print test.help_prop
> #### end of file
> 
> To run the above program, you need to have the strings translated and
> the proper ".po" and ".mo" files created.  (for those interested, I
> can send the whole lot in a zip file)
> 
> If I run the program as is, the output is:
> Aidez-moi!
> AIDE!!!
> 
> Ok, let's try with the Python interpreter:
> 
> ActivePython 2.4.2 Build 248 (ActiveState Corp.) based on
> Python 2.4.2 (#67, Oct 30 2005, 16:11:18) [MSC v.1310 32 bit (Intel)]
> on win32
> Type "help", "copyright", "credits" or "license" for more information.
>>>> import i18n_test
> Aidez-moi!
> AIDE!!!
> 
> #  No surprise there so far.
> 
>>>> print i18n_test.help
> Aidez-moi!
>>>> print i18n_test.test.help_prop
> AIDE!!!
>>>> i18n_test.help
> 'Aidez-moi!'
> 
> # all of the above are as expected; now for the first surprise
> 
>>>> i18n_test.test.help_prop
> Traceback (most recent call last):
>   File "<stdin>", line 1, in ?
>   File "i18n_test.py", line 12, in get
>     __help = _("HELP!")
> TypeError: 'str' object is not callable
> 
> # and a second surprise where we try to repeat something that used to
> work
> 
>>>> print i18n_test.test.help_prop
> Traceback (most recent call last):
>   File "<stdin>", line 1, in ?
>   File "i18n_test.py", line 12, in get
>     __help = _("HELP!")
> TypeError: 'str' object is not callable
> 
> #=============
> 
> Dare I say: "Help!"   I really need to use the above at the
> interpreter prompt.
> 
> André

The _ builtin is set to the result of the last expression evaluated by the
interpreter:

>>> for i in range(3):
...     i
...
0
1
2
>>> _
2
>>> import __builtin__
>>> __builtin__._
2

Therefore you get a name clash with _() as an alias for gettext(). Use
module-global aliases instead, e. g.

_ = fr.gettext

in the above code.

Peter