properly detect hidden (.extension-only) files

babi/highlight.py

@@ -196,16 +196,10 @@ class Grammar(NamedTuple):
 
     @classmethod
     def blank(cls) -> 'Grammar':
-        return cls(
+        return cls.from_data({'scopeName': 'source.unknown', 'patterns': []})
-            scope_name='source.unknown',
-            first_line_match=None,
-            file_types=frozenset(),
-            patterns=(),
-            repository=FDict({}),
-        )
 
     def matches_file(self, filename: str, first_line: str) -> bool:
-        _, ext = os.path.splitext(filename)
+        _, _, ext = os.path.basename(filename).rpartition('.')
         if ext.lstrip('.') in self.file_types:
             return True
         elif self.first_line_match is not None:

tests/highlight_test.py

@@ -4,6 +4,12 @@ from babi.highlight import highlight_line
 from babi.highlight import Region
 
 
+def test_grammar_matches_extension_only_name():
+    data = {'scopeName': 'test', 'patterns': [], 'fileTypes': ['bashrc']}
+    grammar = Grammar.from_data(data)
+    assert grammar.matches_file('.bashrc', 'alias nano=babi')
+
+
 def _compiler_state(grammar_dct, *others):
     grammar = Grammar.from_data(grammar_dct)
     grammars = [grammar, *(Grammar.from_data(dct) for dct in others)]