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# Copyright (c) Meta Platforms, Inc. and affiliates.
# SPDX-License-Identifier: LGPL-2.1-or-later
import ast
from typing import Any, Optional
class NodeVisitor:
"""
Node visitor based on ast.NodeVisitor that also passes the parent node and
(right) sibling node.
"""
def visit(self, node: ast.AST) -> Any:
return self._visit(node, None, None)
def _visit(
self, node: ast.AST, parent: Optional[ast.AST], sibling: Optional[ast.AST]
) -> Any:
method = "visit_" + node.__class__.__name__
visitor = getattr(self, method, None)
if visitor is None:
self.generic_visit(node)
else:
return visitor(node, parent, sibling)
def generic_visit(self, node: ast.AST) -> None:
for field, value in ast.iter_fields(node):
if isinstance(value, list):
prev = None
for item in value:
if isinstance(item, ast.AST):
if prev:
self._visit(prev, node, item)
prev = item
if prev:
self._visit(prev, node, None)
elif isinstance(value, ast.AST):
self._visit(value, node, None)
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