summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
-rw-r--r--Lib/ast.py31
-rw-r--r--Lib/test/test_tokenize.py2
-rw-r--r--Lib/test/test_unparse.py23
-rw-r--r--Misc/NEWS.d/next/Library/2023-09-03-04-37-52.gh-issue-108469.kusj40.rst3
4 files changed, 31 insertions, 28 deletions
diff --git a/Lib/ast.py b/Lib/ast.py
index 45b9596..17ec7ff 100644
--- a/Lib/ast.py
+++ b/Lib/ast.py
@@ -1225,17 +1225,7 @@ class _Unparser(NodeVisitor):
def visit_JoinedStr(self, node):
self.write("f")
- if self._avoid_backslashes:
- with self.buffered() as buffer:
- self._write_fstring_inner(node)
- return self._write_str_avoiding_backslashes("".join(buffer))
-
- # If we don't need to avoid backslashes globally (i.e., we only need
- # to avoid them inside FormattedValues), it's cosmetically preferred
- # to use escaped whitespace. That is, it's preferred to use backslashes
- # for cases like: f"{x}\n". To accomplish this, we keep track of what
- # in our buffer corresponds to FormattedValues and what corresponds to
- # Constant parts of the f-string, and allow escapes accordingly.
+
fstring_parts = []
for value in node.values:
with self.buffered() as buffer:
@@ -1247,11 +1237,14 @@ class _Unparser(NodeVisitor):
new_fstring_parts = []
quote_types = list(_ALL_QUOTES)
for value, is_constant in fstring_parts:
- value, quote_types = self._str_literal_helper(
- value,
- quote_types=quote_types,
- escape_special_whitespace=is_constant,
- )
+ if is_constant:
+ value, quote_types = self._str_literal_helper(
+ value,
+ quote_types=quote_types,
+ escape_special_whitespace=True,
+ )
+ elif "\n" in value:
+ quote_types = [q for q in quote_types if q in _MULTI_QUOTES]
new_fstring_parts.append(value)
value = "".join(new_fstring_parts)
@@ -1273,16 +1266,12 @@ class _Unparser(NodeVisitor):
def visit_FormattedValue(self, node):
def unparse_inner(inner):
- unparser = type(self)(_avoid_backslashes=True)
+ unparser = type(self)()
unparser.set_precedence(_Precedence.TEST.next(), inner)
return unparser.visit(inner)
with self.delimit("{", "}"):
expr = unparse_inner(node.value)
- if "\\" in expr:
- raise ValueError(
- "Unable to avoid backslash in f-string expression part"
- )
if expr.startswith("{"):
# Separate pair of opening brackets as "{ {"
self.write(" ")
diff --git a/Lib/test/test_tokenize.py b/Lib/test/test_tokenize.py
index 7863e27..dbefee6 100644
--- a/Lib/test/test_tokenize.py
+++ b/Lib/test/test_tokenize.py
@@ -1860,7 +1860,7 @@ class TestRoundtrip(TestCase):
testfiles.remove(os.path.join(tempdir, "test_unicode_identifiers.py"))
- # TODO: Remove this once we can unparse PEP 701 syntax
+ # TODO: Remove this once we can untokenize PEP 701 syntax
testfiles.remove(os.path.join(tempdir, "test_fstring.py"))
for f in ('buffer', 'builtin', 'fileio', 'inspect', 'os', 'platform', 'sys'):
diff --git a/Lib/test/test_unparse.py b/Lib/test/test_unparse.py
index b3efb61..38c59e6 100644
--- a/Lib/test/test_unparse.py
+++ b/Lib/test/test_unparse.py
@@ -197,6 +197,10 @@ class UnparseTestCase(ASTTestCase):
self.check_ast_roundtrip('''f"a\\r\\nb"''')
self.check_ast_roundtrip('''f"\\u2028{'x'}"''')
+ def test_fstrings_pep701(self):
+ self.check_ast_roundtrip('f" something { my_dict["key"] } something else "')
+ self.check_ast_roundtrip('f"{f"{f"{f"{f"{f"{1+1}"}"}"}"}"}"')
+
def test_strings(self):
self.check_ast_roundtrip("u'foo'")
self.check_ast_roundtrip("r'foo'")
@@ -378,8 +382,15 @@ class UnparseTestCase(ASTTestCase):
)
)
- def test_invalid_fstring_backslash(self):
- self.check_invalid(ast.FormattedValue(value=ast.Constant(value="\\\\")))
+ def test_fstring_backslash(self):
+ # valid since Python 3.12
+ self.assertEqual(ast.unparse(
+ ast.FormattedValue(
+ value=ast.Constant(value="\\\\"),
+ conversion=-1,
+ format_spec=None,
+ )
+ ), "{'\\\\\\\\'}")
def test_invalid_yield_from(self):
self.check_invalid(ast.YieldFrom(value=None))
@@ -502,11 +513,11 @@ class CosmeticTestCase(ASTTestCase):
self.check_src_roundtrip("class X(*args, **kwargs):\n pass")
def test_fstrings(self):
- self.check_src_roundtrip('''f\'\'\'-{f"""*{f"+{f'.{x}.'}+"}*"""}-\'\'\'''')
- self.check_src_roundtrip('''f"\\u2028{'x'}"''')
+ self.check_src_roundtrip("f'-{f'*{f'+{f'.{x}.'}+'}*'}-'")
+ self.check_src_roundtrip("f'\\u2028{'x'}'")
self.check_src_roundtrip(r"f'{x}\n'")
- self.check_src_roundtrip('''f''\'{"""\n"""}\\n''\'''')
- self.check_src_roundtrip('''f''\'{f"""{x}\n"""}\\n''\'''')
+ self.check_src_roundtrip("f'{'\\n'}\\n'")
+ self.check_src_roundtrip("f'{f'{x}\\n'}\\n'")
def test_docstrings(self):
docstrings = (
diff --git a/Misc/NEWS.d/next/Library/2023-09-03-04-37-52.gh-issue-108469.kusj40.rst b/Misc/NEWS.d/next/Library/2023-09-03-04-37-52.gh-issue-108469.kusj40.rst
new file mode 100644
index 0000000..ac0f682
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2023-09-03-04-37-52.gh-issue-108469.kusj40.rst
@@ -0,0 +1,3 @@
+:func:`ast.unparse` now supports new :term:`f-string` syntax introduced in
+Python 3.12. Note that the :term:`f-string` quotes are reselected for simplicity
+under the new syntax. (Patch by Steven Sun)