internationalize using Babel

this commit also makes the sdist tarball generated by setuptools REUSE-compliant

2 files changed, 30 insertions, 2 deletions

diff --git a/src/hydrilla/util/__init__.py b/src/hydrilla/util/__init__.py
index 2a69e0d..3a13831 100644
--- a/src/hydrilla/util/__init__.py
+++ b/src/hydrilla/util/__init__.py
@@ -5,4 +5,4 @@
 # Available under the terms of Creative Commons Zero v1.0 Universal.
 
 from ._util import strip_json_comments, normalize_version, parse_version, \
-    version_string, validator_for
+    version_string, validator_for, get_gettext
diff --git a/src/hydrilla/util/_util.py b/src/hydrilla/util/_util.py
index 9bebdc1..c7e9f47 100644
--- a/src/hydrilla/util/_util.py
+++ b/src/hydrilla/util/_util.py
@@ -26,6 +26,8 @@
 
 import re
 import json
+import locale
+import gettext
 
 from pathlib import Path
 from typing import Optional
@@ -71,7 +73,7 @@ def strip_json_comments(text: str) -> str:
             # ignore this error, let json module report it
             stripped = line
         elif len(match[2]) == 1:
-            raise json.JSONDecodeError('bad comment', text,
+            raise json.JSONDecodeError(_('bad_comment'), text,
                                        processed + len(match[1]))
         else:
             stripped = match[1]
@@ -127,3 +129,29 @@ def validator_for(schema_filename: str) -> Draft7Validator:
     """
     return Draft7Validator(resolver.resolve(schema_filename)[1],
                            resolver=resolver)
+
+def get_gettext(domain: str, lang: Optional[str]=None):
+    """
+    Configure translation and return its gettext() function.
+
+    If `lang` is set, look for translations for `lang`. Otherwise, try to
+    determine system's default language and use that.
+    """
+    # https://stackoverflow.com/questions/3425294/how-to-detect-the-os-default-language-in-python
+    # But I am not going to surrender to Microbugs' nonfree, crappy OS to test
+    # it, to the lines inside try: may fail.
+    try:
+        from ctypes.windll import kernel32 as windll
+        lang = locale.windows_locale[windll.GetUserDefaultUILanguage()]
+    except:
+        lang = locale.getdefaultlocale()[0] or 'C'
+
+    translation = gettext.translation(
+        domain,
+        localedir=(here.parent / 'locales'),
+        languages=[lang, 'en_US']
+    )
+
+    return translation.gettext
+
+_ = get_gettext('hydrilla_builder')