Fix BETWEEN with leading-dot decimals being mis-lexed (issue601)

CHANGELOG

@@ -33,6 +33,8 @@ Bug Fixes
 
 * Fix statement splitting (issue845).
 * Fix a late-binding closure bug in `TokenList.token_not_matching`.
+* Fix keyword before a leading-dot float being lexed as a name, e.g. in
+  ``BETWEEN .03 AND .06`` (issue601).
 
 
 Release 0.5.5 (Dec 19, 2025)

sqlparse/keywords.py

@@ -49,7 +49,7 @@
     # see issue #39
     # Spaces around period `schema . name` are valid identifier
     # TODO: Spaces before period not implemented
-    (r'[A-ZÀ-Ü]\w*(?=\s*\.)', tokens.Name),  # 'Name'.
+    (r'[A-ZÀ-Ü]\w*(?=\s*\.(?!\d))', tokens.Name),  # 'Name'.
     # FIXME(atronah): never match,
     # because `re.match` doesn't work with look-behind regexp feature
     (r'(?<=\.)[A-ZÀ-Ü]\w*', tokens.Name),  # .'Name'

tests/test_regressions.py

@@ -465,3 +465,16 @@ def limit_recursion():
 def test_max_recursion(limit_recursion):
     with pytest.raises(SQLParseError):
         sqlparse.parse('[' * 1000 + ']' * 1000)
+
+
+def test_between_leading_dot_float_issue601():
+    # a leading-dot float must not turn the preceding word into a Name
+    # by mistaking the decimal point for a qualified-name separator
+    p = sqlparse.parse('a between .03 and .06')[0]
+    tokens = [t for t in p.flatten() if not t.is_whitespace]
+    assert tokens[1].ttype is T.Keyword
+    assert tokens[1].value == 'between'
+    assert tokens[2].ttype is T.Number.Float
+    assert tokens[3].ttype is T.Keyword
+    assert tokens[3].value == 'and'
+    assert tokens[4].ttype is T.Number.Float