First implementation of plurals. This is a bit rough, still.

Added Polish translations to have a complex plural rule handy.
Currently, only german is tested.
We need to test the whole set of languages and probably add more.

9 files changed, 151 insertions, 9 deletions

diff --git a/src/zope/i18n/gettextmessagecatalog.py b/src/zope/i18n/gettextmessagecatalog.py
index 307e5be..884cf54 100644
--- a/src/zope/i18n/gettextmessagecatalog.py
+++ b/src/zope/i18n/gettextmessagecatalog.py
@@ -22,7 +22,12 @@ 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
 
 
 @implementer(IGlobalMessageCatalog)
@@ -33,13 +38,20 @@ 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'
@@ -50,13 +62,35 @@ class GettextMessageCatalog(object):
         'See IMessageCatalog'
         return self._gettext(id)
 
+    def getPluralMessage(self, singular, plural, n):
+        'See IMessageCatalog'
+        msg = self._ngettext(singular, plural, n)
+        try:
+            return msg % n
+        except TypeError:
+            return msg  
+
+    def queryPluralMessage(self, singular, plural, n, dft1=None, dft2=None):
+        'See IMessageCatalog'
+        try:
+            msg = self._ngettext(singular, plural, n)
+        except KeyError:
+            if n == 1:  # Please FIX using the language rule.
+                msg = dft1
+            else:
+                msg = dft2
+        try:
+            return msg % n
+        except TypeError:
+            return msg  
+    
     def queryMessage(self, id, default=None):
         'See IMessageCatalog'
         try:
             return self._gettext(id)
         except KeyError:
             return default
-
+        
     def getIdentifier(self):
         'See IMessageCatalog'
         return self._path_to_file
diff --git a/src/zope/i18n/interfaces/__init__.py b/src/zope/i18n/interfaces/__init__.py
index 397c8f5..187ba16 100644
--- a/src/zope/i18n/interfaces/__init__.py
+++ b/src/zope/i18n/interfaces/__init__.py
@@ -60,13 +60,16 @@ class IMessageCatalog(Interface):
 
         An exception is raised if the message id is not found.
         """
-
+        
     def queryMessage(msgid, default=None):
         """Look for the appropriate text for the given message id.
 
         If the message id is not found, default is returned.
         """
 
+    # FIX ME ADD PLURAL METHODS IF WE DECIDE TO KEEP THEM SEPARATED FROM
+    # THE SINGULAR METHODS.
+        
     language = TextLine(
         title=u"Language",
         description=u"The language the catalog translates to.",
diff --git a/src/zope/i18n/tests/de-default.mo b/src/zope/i18n/tests/de-default.mo
index 392a0ff..f49b8da 100644
--- a/src/zope/i18n/tests/de-default.mo
+++ b/src/zope/i18n/tests/de-default.mo
diff --git a/src/zope/i18n/tests/de-default.po b/src/zope/i18n/tests/de-default.po
index 99a5f8d..7d3b2f6 100644
--- a/src/zope/i18n/tests/de-default.po
+++ b/src/zope/i18n/tests/de-default.po
@@ -6,9 +6,15 @@ msgstr ""
 "MIME-Version: 1.0\n"
 "Content-Type: text/plain; charset=ISO-8859-1\n"
 "Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=2; plural=n != 1;\n"
 
 msgid "short_greeting"
 msgstr "Hallo!"
 
 msgid "greeting"
 msgstr "Hallo $name, wie geht es Dir?"
+
+msgid "There is one file."
+msgid_plural "There are %d files."
+msgstr[0] "Es gibt eine Datei."
+msgstr[1] "Es gibt %d Dateien."
diff --git a/src/zope/i18n/tests/en-default.mo b/src/zope/i18n/tests/en-default.mo
index 4164029..3e9dc9e 100644
--- a/src/zope/i18n/tests/en-default.mo
+++ b/src/zope/i18n/tests/en-default.mo
diff --git a/src/zope/i18n/tests/en-default.po b/src/zope/i18n/tests/en-default.po
index a3d843b..fc45a11 100644
--- a/src/zope/i18n/tests/en-default.po
+++ b/src/zope/i18n/tests/en-default.po
@@ -6,9 +6,15 @@ msgstr ""
 "MIME-Version: 1.0\n"
 "Content-Type: text/plain; charset=ISO-8859-1\n"
 "Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=2; plural=n != 1;\n"
 
 msgid "short_greeting"
 msgstr "Hello!"
 
 msgid "greeting"
 msgstr "Hello $name, how are you?"
+
+msgid "There is one file."
+msgid_plural "There are %d files."
+msgstr[0] "There is one file."
+msgstr[1] "There are %d files."
diff --git a/src/zope/i18n/tests/pl-default.po b/src/zope/i18n/tests/pl-default.po
new file mode 100644
index 0000000..92a0183
--- /dev/null
+++ b/src/zope/i18n/tests/pl-default.po
@@ -0,0 +1,22 @@
+msgid ""
+msgstr ""
+"Project-Id-Version: Zope 3\n"
+"PO-Revision-Date: 2018-09-04 11:05+0100\n"
+"Last-Translator: Zope 3 contributors\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=ISO-8859-2\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=3; plural=n==1 ? 0 : n%10>=2 && n%10<=4 && (n%100<10 || n%100>=20) ? 1 : 2;\n"
+
+
+msgid "short_greeting"
+msgstr "Cześć !"
+
+msgid "greeting"
+msgstr "Cześć $name, jak siê masz?"
+
+msgid "There is %d file."
+msgid_plural "There are %d files."
+msgstr[0] "Istnieje %d plik."
+msgstr[1] "Istnieją %d pliki."
+msgstr[2] "Istnieją %d plików."
diff --git a/src/zope/i18n/tests/test_imessagecatalog.py b/src/zope/i18n/tests/test_imessagecatalog.py
index 2856c67..803d4f0 100644
--- a/src/zope/i18n/tests/test_imessagecatalog.py
+++ b/src/zope/i18n/tests/test_imessagecatalog.py
@@ -43,24 +43,20 @@ class TestIMessageCatalog(unittest.TestCase):
         self.assertEqual(catalog.getMessage('short_greeting'), 'Hello!')
         self.assertRaises(KeyError, catalog.getMessage, 'foo')
 
-
     def testQueryMessage(self):
         catalog = self._catalog
         self.assertEqual(catalog.queryMessage('short_greeting'), 'Hello!')
         self.assertEqual(catalog.queryMessage('foo'), None)
         self.assertEqual(catalog.queryMessage('foo', 'bar'), 'bar')
 
-
     def testGetLanguage(self):
         catalog = self._catalog
         self.assertEqual(catalog.language, 'en')
 
-
     def testGetDomain(self):
         catalog = self._catalog
         self.assertEqual(catalog.domain, 'default')
 
-
     def testGetIdentifier(self):
         catalog = self._catalog
         self.assertEqual(catalog.getIdentifier(), self._getUniqueIndentifier())
diff --git a/src/zope/i18n/tests/test_plurals.py b/src/zope/i18n/tests/test_plurals.py
new file mode 100644
index 0000000..435e670
--- /dev/null
+++ b/src/zope/i18n/tests/test_plurals.py
@@ -0,0 +1,75 @@
+##############################################################################
+#
+# Copyright (c) 2001, 2002 Zope Foundation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE.
+#
+##############################################################################
+"""Test a gettext implementation of a Message Catalog.
+"""
+import os
+import unittest
+from zope.i18n import tests
+from zope.i18n.gettextmessagecatalog import GettextMessageCatalog
+from zope.i18n.tests import test_imessagecatalog
+
+
+class TestPlurals(unittest.TestCase):
+
+    def _getMessageCatalog(self, locale, variant="default"):
+        path = os.path.dirname(tests.__file__)
+        self._path = os.path.join(path, '%s-%s.mo' % (locale, variant))
+        catalog = GettextMessageCatalog(locale, variant, self._path)
+        return catalog
+
+    def test_GermanMessages(self):
+        catalog = self._getMessageCatalog('de')
+        self.assertEqual(catalog.language, 'de')
+
+        self.assertEqual(catalog.getPluralMessage(
+                         'There is one file.', 'There are %d files.', 1),
+                         'Es gibt eine Datei.')
+        self.assertEqual(catalog.getPluralMessage(
+                         'There is one file.', 'There are %d files.', 3),
+                         'Es gibt 3 Dateien.')
+
+        self.assertEqual(catalog.getPluralMessage(
+                         'There is one file.', 'There are %d files.', 0),
+                         'Es gibt 0 Dateien.')
+        
+        # Unknown id
+        self.assertRaises(KeyError, catalog.getPluralMessage, 
+                          'There are %d files.', 'bar', 6)
+
+        # Query without default values
+        self.assertEqual(catalog.queryPluralMessage(
+                         'There is one file.', 'There are %d files.', 1),
+                         'Es gibt eine Datei.')
+        self.assertEqual(catalog.queryPluralMessage(
+                         'There is one file.', 'There are %d files.', 3),
+                         'Es gibt 3 Dateien.')
+
+        # Query with default values
+        self.assertEqual(catalog.queryPluralMessage(
+                         'There are %d files.', 'There is one file.', 1,
+                         'Es gibt 1 Datei.', 'Es gibt %d Dateien !', ),
+                         'Es gibt 1 Datei.')
+        self.assertEqual(catalog.queryPluralMessage(
+                         'There are %d files.', 'There is one file.', 3,
+                         'Es gibt 1 Datei.', 'Es gibt %d Dateien !', ),
+                         'Es gibt 3 Dateien !')
+
+
+def test_suite():
+    return unittest.TestSuite((
+        unittest.makeSuite(TestPlurals),
+    ))
+
+if __name__ == '__main__':
+    unittest.main(defaultTest='test_suite')