mirror of
https://github.com/python/cpython.git
synced 2025-07-22 18:55:22 +00:00
Fix 'gather' rules in the python parser generator (GH-22021)
Currently, empty sequences in gather rules make the conditional for gather rules fail as empty sequences evaluate as "False". We need to explicitly check for "None" (the failure condition) to avoid false negatives.
This commit is contained in:
parent
315a61f7a9
commit
e55a0e971b
2 changed files with 18 additions and 1 deletions
|
@ -74,7 +74,7 @@ class TestPegen(unittest.TestCase):
|
|||
"Rule('term', 'int', Rhs([Alt([NamedItem(None, NameLeaf('NUMBER'))])]))"
|
||||
)
|
||||
|
||||
def test_repeat_with_separator_rules(self) -> None:
|
||||
def test_gather(self) -> None:
|
||||
grammar = """
|
||||
start: ','.thing+ NEWLINE
|
||||
thing: NUMBER
|
||||
|
@ -85,6 +85,20 @@ class TestPegen(unittest.TestCase):
|
|||
"Rule('start', None, Rhs([Alt([NamedItem(None, Gather(StringLeaf(\"','\"), NameLeaf('thing'"
|
||||
))
|
||||
self.assertEqual(str(rules["thing"]), "thing: NUMBER")
|
||||
parser_class = make_parser(grammar)
|
||||
node = parse_string("42\n", parser_class)
|
||||
assert node == [
|
||||
[[TokenInfo(NUMBER, string="42", start=(1, 0), end=(1, 2), line="42\n")]],
|
||||
TokenInfo(NEWLINE, string="\n", start=(1, 2), end=(1, 3), line="42\n"),
|
||||
]
|
||||
node = parse_string("1, 2\n", parser_class)
|
||||
assert node == [
|
||||
[
|
||||
[TokenInfo(NUMBER, string="1", start=(1, 0), end=(1, 1), line="1, 2\n")],
|
||||
[TokenInfo(NUMBER, string="2", start=(1, 3), end=(1, 4), line="1, 2\n")],
|
||||
],
|
||||
TokenInfo(NEWLINE, string="\n", start=(1, 4), end=(1, 5), line="1, 2\n"),
|
||||
]
|
||||
|
||||
def test_expr_grammar(self) -> None:
|
||||
grammar = """
|
||||
|
|
|
@ -217,6 +217,9 @@ class PythonParserGenerator(ParserGenerator, GrammarVisitor):
|
|||
else:
|
||||
self.print("and")
|
||||
self.visit(item)
|
||||
if is_gather:
|
||||
self.print("is not None")
|
||||
|
||||
self.print("):")
|
||||
with self.indent():
|
||||
action = node.action
|
||||
|
|
Loading…
Add table
Add a link
Reference in a new issue