add get_str_list() for config

Converts a config value written as a comma-sparated list into
a Python list of strings.

nominatim/clicmd/setup.py

@@ -128,7 +128,7 @@ class SetupAll:
                                                   drop=args.no_updates)
             LOG.warning('Create search index for default country names.')
             country_info.create_country_names(conn, tokenizer,
-                                              args.config.LANGUAGES)
+                                              args.config.get_str_list('LANGUAGES'))
             if args.no_updates:
                 freeze.drop_update_tables(conn)
         tokenizer.finalize_import(args.config)

nominatim/config.py

@@ -99,6 +99,17 @@ class Configuration:
             raise UsageError("Configuration error.") from exp
 
 
+    def get_str_list(self, name):
+        """ Return the given configuration parameter as a list of strings.
+            The values are assumed to be given as a comma-sparated list and
+            will be stripped before returning them. On empty values None
+            is returned.
+        """
+        raw = self.__getattr__(name)
+
+        return [v.strip() for v in raw.split(',')] if raw else None
+
+
     def get_path(self, name):
         """ Return the given configuration parameter as a Path.
             If a relative path is configured, then the function converts this

nominatim/tools/country_info.py

@@ -131,9 +131,6 @@ def create_country_names(conn, tokenizer, languages=None):
         empty then only name translations for the given languages are added
         to the index.
     """
-    if languages:
-        languages = languages.split(',')
-
     def _include_key(key):
         return ':' not in key or not languages or \
                key[key.index(':') + 1:] in languages