enable deferred translation of date format strings

gramps/gen/datehandler/_datedisplay.py

@@ -44,6 +44,10 @@ from . import _grampslocale
 from ..utils.grampslocale import GrampsLocale
 from ._datestrings import DateStrings
 
+# _T_ is a gramps-defined keyword -- see po/update_po.py and po/genpot.sh
+def _T_(value): # enable deferred translations (see Python docs 22.1.3.4)
+    return value
+
 #-------------------------------------------------------------------------
 #
 # DateDisplay
@@ -53,33 +57,31 @@ class DateDisplay:
     """
     Base date display class.
     """
-    _locale = GrampsLocale(lang='en_US', languages='en')
 
     _tformat = _grampslocale.tformat
 
-    _ = _grampslocale.glocale.translation.sgettext
     formats = (
         # format 0 - must always be ISO
-        _("YYYY-MM-DD (ISO)"),
+        _T_("YYYY-MM-DD (ISO)"),
 
         # format # 1 - must always be locale-preferred numerical format
         # such as YY.MM.DD, MM-DD-YY, or whatever your locale prefers.
         # This should be the format that is used under the locale by
         # strftime() for '%x'.
         # You may translate this as "Numerical", "System preferred", or similar.
-        _("date format|Numerical"),
+        _T_("date format|Numerical"),
 
         # Full month name, day, year
-        _("Month Day, Year"),
+        _T_("Month Day, Year"),
 
         # Abbreviated month name, day, year
-        _("MON DAY, YEAR"),
+        _T_("MON DAY, YEAR"),
 
         # Day, full month name, year
-        _("Day Month Year"),
+        _T_("Day Month Year"),
 
         # Day, abbreviated month name, year
-        _("DAY MON YEAR")
+        _T_("DAY MON YEAR")
         )
     """
     .. note:: Will be overridden if a locale-specific date displayer exists.
@@ -90,7 +92,6 @@ class DateDisplay:
     This ``formats`` must agree with
     :meth:`~_display_calendar`/:meth:`~_display_gregorian`.
     """
-    del _
 
     newyear = ("", "Mar1", "Mar25", "Sep1")
 
@@ -728,4 +729,4 @@ class DateDisplayEn(DateDisplay):
 
     display = DateDisplay.display_formatted
 
-    _locale = DateDisplay._locale # normally set in register_datehandler
+    _locale = GrampsLocale(languages='en') # no register_datehandler here

gramps/gen/datehandler/_dateutils.py

@@ -34,6 +34,7 @@ import time
 # Gramps modules
 #
 #-------------------------------------------------------------------------
+from ..const import GRAMPS_LOCALE as glocale
 from ..lib.date import Date
 from . import LANG_TO_DISPLAY, LANG, parser, displayer
 
@@ -42,14 +43,22 @@ from . import LANG_TO_DISPLAY, LANG, parser, displayer
 # Convenience functions
 #
 #--------------------------------------------------------------
-def get_date_formats():
+def get_date_formats(flocale=glocale):
     """
     Return the list of supported formats for date parsers and displayers.
+    The UI language formats will be used unless another locale is fed in.
+
+    :param flocale: allow deferred translation of date formats
+    :type flocale: a :class:`.GrampsLocale` instance
     """
+    # trans_text is a defined keyword (see po/update_po.py, po/genpot.sh)
+    trans_text = flocale.translation.sgettext
     try:
-        return LANG_TO_DISPLAY[LANG].formats
+        return tuple(trans_text(fmt)
+                     for fmt in LANG_TO_DISPLAY[flocale.lang].formats)
     except:
-        return LANG_TO_DISPLAY["C"].formats
+        return tuple(trans_text(fmt)
+                     for fmt in LANG_TO_DISPLAY['C'].formats)
 
 def set_format(value):
     try:

gramps/gen/datehandler/test/datedisplay_test.py

@@ -30,8 +30,8 @@ from ...lib.date import Date
 
 class DateDisplayTest(unittest.TestCase):
     def setUp(self):
-        from .._datedisplay import DateDisplay
-        self.display = DateDisplay()
+        from .._datedisplay import DateDisplayEn
+        self.display = DateDisplayEn()
         self.display_RU = GrampsLocale(lang='ru').date_displayer
 
     def assert_map_key_val(self, m, k, v):