implement gettext localization for python

make gnc_path_get_localedir() and GETTEXT_PACKAGE available for python
to access locales. Import gettext module to provide _ as translator
method. Provide null _-method returning english text in case of missing gettext.
Make a lot of messages translatable by adding _-method. Include python
files to create .pot-files.

bindings/core-utils.i

@@ -57,6 +57,12 @@ gchar * gnc_path_get_scmdir(void);
 %newobject gnc_path_get_reportsdir;
 gchar * gnc_path_get_reportsdir(void);
 
+%newobject gnc_path_get_localedir;
+gchar * gnc_path_get_localedir(void);
+
+/* Name of our gettext-domain (defined in config.h) */
+%constant char* GETTEXT_PACKAGE = GETTEXT_PACKAGE;
+
 %newobject gnc_path_get_stdreportsdir;
 gchar * gnc_path_get_stdreportsdir(void);
 

bindings/python/gnucash_core.py

@@ -28,7 +28,8 @@
 #  @author Jeff Green,   ParIT Worker Co-operative <jeff@parit.ca>
 #  @ingroup python_bindings
 
-import gnucash.gnucash_core_c as gnucash_core_c
+from gnucash import gnucash_core_c
+from gnucash import _sw_core_utils
 
 from gnucash.function_class import \
      ClassFromFunctions, extract_attributes_with_prefix, \
@@ -46,6 +47,24 @@ from gnucash.gnucash_core_c import gncInvoiceLookup, gncInvoiceGetInvoiceFromTxn
     gnc_numeric_create, double_to_gnc_numeric, string_to_gnc_numeric, \
     gnc_numeric_to_string
 
+try:
+    import gettext
+    # install gettext for _-function, needs path to locales
+    _localedir = _sw_core_utils.gnc_path_get_localedir()
+    _translation = gettext.translation(_sw_core_utils.GETTEXT_PACKAGE, _localedir)
+    _ = _translation.gettext
+except:
+    print("\nProblem importing gettext!")
+    import traceback
+    import sys
+    exc_type, exc_value, exc_traceback = sys.exc_info()
+    traceback.print_exception(exc_type, exc_value, exc_traceback)
+    print()
+
+    def _(s):
+        """Null translator function, gettext not available"""
+        return s
+
 class GnuCashCoreClass(ClassFromFunctions):
     _module = gnucash_core_c
 

gnucash/python/init.py

@@ -1,16 +1,22 @@
 import sys
 from gnucash import *
+from gnucash import _sw_app_utils
+from gnucash import _sw_core_utils
 from gnucash._sw_core_utils import gnc_prefs_is_extra_enabled, gnc_prefs_is_debugging_enabled
+from gnucash.gnucash_core import _
 from gi import require_version
 require_version('Gtk', '3.0')
 from gi.repository import Gtk
 import os
+
 sys.path.append(os.path.dirname(__file__))
 
 # output file location if gnucash has been started with
 # gnucash --extra
 if gnc_prefs_is_extra_enabled():
     print("Python shell init file: %s" % (__file__))
+    print("\n" + "The following string should appear translated in your preferred language:" + "\n")
+    print("\n" + _("Welcome to GnuCash") +"\n")
 
 # Importing the console class causes SIGTTOU to be thrown if GnuCash is
 # started in the background.  This causes a hang if it is not handled, 

po/CMakeLists.txt

@@ -75,7 +75,7 @@ function(make_gnucash_potfiles)
     ${CMAKE_SOURCE_DIR}/*.glade ${CMAKE_SOURCE_DIR}/*.desktop.in.in
     ${CMAKE_SOURCE_DIR}/*.gschema.xml.in ${CMAKE_SOURCE_DIR}/*.appdata.xml.in.in
     ${CMAKE_SOURCE_DIR}/*.keys.in ${CMAKE_SOURCE_DIR}/*.scm
-    ${CMAKE_SOURCE_DIR}/*/qofbookslots.h
+    ${CMAKE_SOURCE_DIR}/*.py ${CMAKE_SOURCE_DIR}/*/qofbookslots.h
     ${CMAKE_SOURCE_DIR}/*/gnc-commodity.h
   )