1 files changed, 45 insertions, 3 deletions
diff --git a/src/zope/i18n/gettextmessagecatalog.py b/src/zope/i18n/gettextmessagecatalog.py
index 307e5be..99f1951 100644
--- a/src/zope/i18n/gettextmessagecatalog.py
+++ b/src/zope/i18n/gettextmessagecatalog.py
@@ -14,6 +14,7 @@
 """A simple implementation of a Message Catalog.
 """
 
+from functools import wraps
 from gettext import GNUTranslations
 from zope.i18n.interfaces import IGlobalMessageCatalog
 from zope.interface import implementer
@@ -22,7 +23,24 @@ from zope.interface import implementer
 class _KeyErrorRaisingFallback(object):
     def ugettext(self, message):
         raise KeyError(message)
+
+    def ungettext(self, singular, plural, n):
+        raise KeyError(singular)
+
     gettext = ugettext
+    ngettext = ungettext
+
+
+def plural_formatting(func):
+    @wraps(func)
+    def pformat(catalog, singular, plural, n, *args, **kwargs):
+        msg = func(catalog, singular, plural, n, *args, **kwargs)
+        try:
+            return msg % n
+        except TypeError:
+            # The message cannot be formatted : return it "raw".
+            return msg
+    return pformat
 
 
 @implementer(IGlobalMessageCatalog)
@@ -33,13 +51,20 @@ class GettextMessageCatalog(object):
 
     def __init__(self, language, domain, path_to_file):
         """Initialize the message catalog"""
-        self.language = language.decode('utf-8') if isinstance(language, bytes) else language
-        self.domain = domain.decode("utf-8") if isinstance(domain, bytes) else domain
+        self.language = (
+            language.decode('utf-8') if isinstance(language, bytes)
+            else language)
+        self.domain = (
+            domain.decode("utf-8") if isinstance(domain, bytes)
+            else domain)
         self._path_to_file = path_to_file
         self.reload()
         catalog = self._catalog
         catalog.add_fallback(_KeyErrorRaisingFallback())
-        self._gettext = catalog.gettext if str is not bytes else catalog.ugettext
+        self._gettext = (
+            catalog.gettext if str is not bytes else catalog.ugettext)
+        self._ngettext = (
+            catalog.ngettext if str is not bytes else catalog.ungettext)
 
     def reload(self):
         'See IMessageCatalog'
@@ -50,6 +75,23 @@ class GettextMessageCatalog(object):
         'See IMessageCatalog'
         return self._gettext(id)
 
+    @plural_formatting
+    def getPluralMessage(self, singular, plural, n):
+        'See IMessageCatalog'
+        return self._ngettext(singular, plural, n)
+
+    @plural_formatting
+    def queryPluralMessage(self, singular, plural, n, dft1=None, dft2=None):
+        'See IMessageCatalog'
+        try:
+            return self._ngettext(singular, plural, n)
+        except KeyError:
+            # Here, we use the catalog plural function to determine
+            # if `n` triggers a plural form or not.
+            if self._catalog.plural(n):
+                return dft2
+            return dft1
+
     def queryMessage(self, id, default=None):
         'See IMessageCatalog'
         try: