Add support for `msgctxt`. See #54.

1 files changed, 173 insertions, 0 deletions

diff --git a/babel/support.py b/babel/support.py
index ddc0894..20eac91 100644
--- a/babel/support.py
+++ b/babel/support.py
@@ -19,6 +19,7 @@ in applications.
 
 from datetime import date, datetime, time, timedelta
 import gettext
+import locale
 
 from babel.core import Locale
 from babel.dates import format_date, format_datetime, format_time, \
@@ -404,3 +405,175 @@ class Translations(gettext.GNUTranslations, object):
         domain.
         """
         return self._domains.get(domain, self).ungettext(singular, plural, num)
+
+    # Most of the downwards code, until it get's included in stdlib, from:
+    #    http://bugs.python.org/file10036/gettext-pgettext.patch
+    #    
+    # The encoding of a msgctxt and a msgid in a .mo file is
+    # msgctxt + "\x04" + msgid (gettext version >= 0.15)
+    CONTEXT_ENCODING = '%s\x04%s'
+
+    def pgettext(self, context, message):
+        """Look up the `context` and `message` id in the catalog and return the
+        corresponding message string, as an 8-bit string encoded with the
+        catalog's charset encoding, if known.  If there is no entry in the
+        catalog for the `message` id and `context` , and a fallback has been
+        set, the look up is forwarded to the fallback's ``pgettext()``
+        method. Otherwise, the `message` id is returned.
+        """
+        ctxt_msg_id = self.CONTEXT_ENCODING % (context, message)
+        missing = object()
+        tmsg = self._catalog.get(ctxt_msg_id, missing)
+        if tmsg is missing:
+            if self._fallback:
+                return self._fallback.pgettext(context, message)
+            return message
+        # Encode the Unicode tmsg back to an 8-bit string, if possible
+        if self._output_charset:
+            return tmsg.encode(self._output_charset)
+        elif self._charset:
+            return tmsg.encode(self._charset)
+        return tmsg
+
+    def lpgettext(self, context, message):
+        """Equivalent to ``pgettext()``, but the translation is returned in the
+        preferred system encoding, if no other encoding was explicitly set with
+        ``bind_textdomain_codeset()``.
+        """
+        ctxt_msg_id = self.CONTEXT_ENCODING % (context, message)
+        missing = object()
+        tmsg = self._catalog.get(ctxt_msg_id, missing)
+        if tmsg is missing:
+            if self._fallback:
+                return self._fallback.lpgettext(context, message)
+            return message
+        if self._output_charset:
+            return tmsg.encode(self._output_charset)
+        return tmsg.encode(locale.getpreferredencoding())
+
+    def npgettext(self, context, singular, plural, num):
+        """Do a plural-forms lookup of a message id.  `singular` is used as the
+        message id for purposes of lookup in the catalog, while `num` is used to
+        determine which plural form to use.  The returned message string is an
+        8-bit string encoded with the catalog's charset encoding, if known.
+        
+        If the message id for `context` is not found in the catalog, and a
+        fallback is specified, the request is forwarded to the fallback's
+        ``npgettext()`` method.  Otherwise, when ``num`` is 1 ``singular`` is
+        returned, and ``plural`` is returned in all other cases.
+        """
+        ctxt_msg_id = self.CONTEXT_ENCODING % (context, singular)
+        try:
+            tmsg = self._catalog[(ctxt_msg_id, self.plural(num))]
+            if self._output_charset:
+                return tmsg.encode(self._output_charset)
+            elif self._charset:
+                return tmsg.encode(self._charset)
+            return tmsg
+        except KeyError:
+            if self._fallback:
+                return self._fallback.npgettext(context, singular, plural, num)
+            if num == 1:
+                return singular
+            else:
+                return plural
+
+    def lnpgettext(self, context, singular, plural, num):
+        """Equivalent to ``npgettext()``, but the translation is returned in the
+        preferred system encoding, if no other encoding was explicitly set with
+        ``bind_textdomain_codeset()``.
+        """
+        ctxt_msg_id = self.CONTEXT_ENCODING % (context, singular)
+        try:
+            tmsg = self._catalog[(ctxt_msg_id, self.plural(num))]
+            if self._output_charset:
+                return tmsg.encode(self._output_charset)
+            return tmsg.encode(locale.getpreferredencoding())
+        except KeyError:
+            if self._fallback:
+                return self._fallback.lnpgettext(context, singular, plural, num)
+            if num == 1:
+                return singular
+            else:
+                return plural
+
+    def upgettext(self, context, message):
+        """Look up the `context` and `message` id in the catalog and return the
+        corresponding message string, as a Unicode string.  If there is no entry
+        in the catalog for the `message` id and `context`, and a fallback has
+        been set, the look up is forwarded to the fallback's ``upgettext()``
+        method.  Otherwise, the `message` id is returned.
+        """
+        ctxt_message_id = self.CONTEXT_ENCODING % (context, message)
+        missing = object()
+        tmsg = self._catalog.get(ctxt_message_id, missing)
+        if tmsg is missing:
+            if self._fallback:
+                return self._fallback.upgettext(context, message)
+            return unicode(message)
+        return tmsg
+
+    def unpgettext(self, context, singular, plural, num):
+        """Do a plural-forms lookup of a message id.  `singular` is used as the
+        message id for purposes of lookup in the catalog, while `num` is used to
+        determine which plural form to use.  The returned message string is a
+        Unicode string.
+        
+        If the message id for `context` is not found in the catalog, and a
+        fallback is specified, the request is forwarded to the fallback's
+        ``unpgettext()`` method.  Otherwise, when `num` is 1 `singular` is
+        returned, and `plural` is returned in all other cases.
+        """
+        ctxt_message_id = self.CONTEXT_ENCODING % (context, singular)
+        try:
+            tmsg = self._catalog[(ctxt_message_id, self.plural(num))]
+        except KeyError:
+            if self._fallback:
+                return self._fallback.unpgettext(context, singular, plural, num)
+            if num == 1:
+                tmsg = unicode(singular)
+            else:
+                tmsg = unicode(plural)
+        return tmsg
+
+    def dpgettext(self, domain, context, message):
+        """Like `pgettext()`, but look the message up in the specified
+        `domain`.
+        """
+        return self._domains.get(domain, self).pgettext(context, message)
+    
+    def dupgettext(self, domain, context, message):
+        """Like `upgettext()`, but look the message up in the specified
+        `domain`.
+        """
+        return self._domains.get(domain, self).upgettext(context, message)
+
+    def ldpgettext(self, domain, context, message):
+        """Equivalent to ``dpgettext()``, but the translation is returned in the
+        preferred system encoding, if no other encoding was explicitly set with
+        ``bind_textdomain_codeset()``.
+        """
+        return self._domains.get(domain, self).lpgettext(context, message)
+
+    def dnpgettext(self, domain, context, singular, plural, num):
+        """Like ``npgettext``, but look the message up in the specified
+        `domain`.
+        """
+        return self._domains.get(domain, self).npgettext(context, singular,
+                                                         plural, num)
+        
+    def dunpgettext(self, domain, context, singular, plural, num):
+        """Like ``unpgettext``, but look the message up in the specified
+        `domain`.
+        """
+        return self._domains.get(domain, self).unpgettext(context, singular,
+                                                          plural, num)
+
+    def ldnpgettext(self, domain, context, singular, plural, num):
+        """Equivalent to ``dnpgettext()``, but the translation is returned in
+        the preferred system encoding, if no other encoding was explicitly set
+        with ``bind_textdomain_codeset()``.
+        """
+        return self._domains.get(domain, self).lnpgettext(context, singular,
+                                                          plural, num)
+