Enable use of Python <3.11

setup.py

@@ -193,7 +193,8 @@ def run(self):
         'pillow>=8.3.2',
         'pygobject>=3.40.1',
         'sqlalchemy>=1.4.36,<2',
-        'tomli_w>=1.0.0',
+        'tomli_w>=1.0.0;python_version>="3.11"',
+        'toml=0.10.2;python_version<"3.11"',
         'recipe-scrapers>=14.27.0',
     ],
     extras_require={

src/gourmand/prefs.py

@@ -1,9 +1,14 @@
 import shutil
 from pathlib import Path
 from typing import Any, Optional
+import sys
 
-import tomllib
-import tomli_w
+if sys.version_info >= (3, 11):
+    import tomllib.load as tom_load
+    import tomli_w.dump as tom_dump
+else:
+    import tomli.load as tom_load
+    import tomli.dump as tom_dump
 
 from gourmand.gglobals import gourmanddir
 
@@ -33,12 +38,12 @@ def get(self, key: str, default: Optional[Any] = None) -> Optional[Any]:
     def save(self):
         self.filename.parent.mkdir(exist_ok=True)
         with open(self.filename, 'w') as fout:
-            tomli_w.dump(self, fout)
+            tom_dump(self, fout)
 
     def load(self) -> bool:
         if self.filename.is_file():
             with open(self.filename) as fin:
-                for k, v in tomllib.load(fin).items():
+                for k, v in tom_load(fin).items():
                     self.__setitem__(k, v)
             return True
         return False
@@ -55,7 +60,7 @@ def update_preferences_file_format(target_dir: Path = gourmanddir):
         return
 
     with open(filename) as fin:
-        prefs = tomllib.load(fin)
+        prefs = tom_load(fin)
 
     # Gourmand 1.2.0: several sorting parameters can be saved.
     # The old format had `column=name` and `ascending=bool`, which are now `name=bool`
@@ -65,7 +70,7 @@ def update_preferences_file_format(target_dir: Path = gourmanddir):
             prefs['sort_by'] = {sort_by['column']: sort_by['ascending']}
 
     with open(filename, 'w') as fout:
-        tomli_w.dump(prefs, fout)
+        tom_dump(prefs, fout)
 
 
 def copy_old_installation_or_initialize(target_dir: Path):

tests/test_prefs.py

@@ -1,6 +1,12 @@
 import pytest
-import tomllib
-import tomli_w
+import sys
+
+if sys.version_info >= (3, 11):
+    import tomllib.load as tom_load
+    import tomli_w.dump as tom_dump
+else:
+    import tomli.load as tom_load
+    import tomli.dump as tom_dump
 
 from pathlib import Path
 
@@ -38,22 +44,22 @@ def test_update_preferences_file_format(tmpdir):
     filename = tmpdir.join('preferences.toml')
 
     with open(filename, 'w') as fout:
-        tomli_w.dump({'sort_by': {'column': 'title', 'ascending': True}}, fout)
+        tom_dump({'sort_by': {'column': 'title', 'ascending': True}}, fout)
 
     update_preferences_file_format(Path(tmpdir))
 
     with open(filename) as fin:
-        d = tomllib.load(fin)
+        d = tom_load(fin)
 
     assert 'category' not in d['sort_by'].keys()
     assert d['sort_by']['title'] == True
 
     with open(filename, 'w') as fout:
-        tomli_w.dump({}, fout)
+        tom_dump({}, fout)
 
     update_preferences_file_format(Path(tmpdir))
 
     with open(filename) as fin:
-        d = tomllib.load(fin)
+        d = tom_load(fin)
 
     assert d == {}