Ticket #19160: 19160-1.diff

django/utils/functional.py

@@ -153 +153 @@
         __hash__ = object.__hash__
 
         def __mod__(self, rhs):
+            if hasattr(self, '_mod_key') and self._mod_key in rhs:
+                self.__args = self.__args[:-1] + (rhs[self._mod_key],)
             if self._delegate_bytes and not six.PY3:
                 return bytes(self) % rhs
             elif self._delegate_text:
@@ -170 +172 @@
     @wraps(func)
     def __wrapper__(*args, **kw):
         # Creates the proxy object, instead of the actual value.
-        return __proxy__(args, kw)
+        proxy = __proxy__(args, kw)
+        if (func.__name__ in ('ngettext', 'ungettext', 'npgettext') and
+                isinstance(args[-1], six.string_types):
+            proxy._mod_key = args[-1]
+        return proxy
 
     return __wrapper__
 

docs/ref/utils.txt

@@ -747 +747 @@
 
 .. function:: ngettext_lazy(singular, plural, number)
 .. function:: ungettext_lazy(singular, plural, number)
-.. function:: npgettext_lazy(singular, plural, number)
+.. function:: npgettext_lazy(context, singular, plural, number)
 
-    Same as the non-lazy versions above, but using lazy execution.
+    Same as the non-lazy versions above, but using lazy execution. As most of
+    the time, the ``number`` argument is not known at the time you call a lazy
+    function, you can also pass a dictionary key name in ``number`` which will
+    have to match a dictionary key at string interpolation time.
 
     See :ref:`lazy translations documentation <lazy-translations>`.
 

docs/topics/i18n/translation.txt

@@ -408 +408 @@
 (so that the correct locale is in effect). This necessitates the use of the
 helper function described next.
 
+Lazy translations and plural
+----------------------------
+
+.. versionadded:: 1.5
+
+When using lazy translation for a plural string (``[u]n[p]gettext_lazy``), you
+generally don't know the ``number`` argument at the time of the string
+definition. Therefore, you are authorized to pass a dictionary key name in place
+of an integer as the ``number`` argument. Then, when the string is effectively
+translated with a placeholders dictionary, the ``number`` argument will get
+substituted by the value of the key in the dictionary::
+
+    class MyForm(forms.Form):
+        error_message = ungettext_lazy("You only provide %(num)d argument",
+             "You only provide %(num)d arguments", 'num')
+
+        def clean(self):
+            ...
+            raise forms.ValidationError(self.error_message % {'num': number})
+
 Joining strings: string_concat()
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

tests/regressiontests/i18n/other/locale/de/LC_MESSAGES/django.po

@@ -35 +35 @@
 msgstr "Kann"
 
 #: models.py:11
+msgid "%(num)d good result"
+msgid_plural "%(num)d good results"
+msgstr[0] "%(num)d gutes Resultat"
+msgstr[1] "%(num)d guten Resultate"
+
+#: models.py:11
 msgctxt "search"
 msgid "%d result"
 msgid_plural "%d results"
@@ -75 +81 @@
 #: models.py:23
 msgctxt "other comment count"
 msgid "There are %(num_comments)s comments"
-msgstr "Andere: Es gibt %(num_comments)s Kommentare"
- No newline at end of file
+msgstr "Andere: Es gibt %(num_comments)s Kommentare"

tests/regressiontests/i18n/tests.py

@@ -22 +22 @@
 from django.utils import six
 from django.utils.six import PY3
 from django.utils.translation import (ugettext, ugettext_lazy, activate,
-    deactivate, gettext_lazy, pgettext, npgettext, to_locale,
+    deactivate, gettext_lazy, ungettext_lazy, pgettext, npgettext, to_locale,
     get_language_info, get_language, get_language_from_request, trans_real)
 
 
@@ -50 +50 @@
 )
 
 class TranslationTests(TestCase):
-
     def test_override(self):
         activate('de')
         with translation.override('pl'):
@@ -90 +89 @@
         self.assertEqual(six.text_type(s2), "test")
 
     @override_settings(LOCALE_PATHS=extended_locale_paths)
+    def test_ungettext_lazy(self):
+        s1 = ungettext_lazy("%(num)d good result", "%(num)d good results", 4)
+        s2 = ungettext_lazy("%(num)d good result", "%(num)d good results", 'num')
+        with translation.override('de'):
+            # s1 form not very useful, as number arg is fixed at definition time
+            self.assertEqual(s1 % {'num': 1}, "1 guten Resultate")
+            self.assertEqual(s2 % {'num': 1}, "1 gutes Resultat")
+            self.assertEqual(s2 % {'num': 4}, "4 guten Resultate")
+
+    @override_settings(LOCALE_PATHS=extended_locale_paths)
     def test_pgettext(self):
         trans_real._active = local()
         trans_real._translations = {}