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Visitor.py
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Visitor.py
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# Copyright 2019 IBM Corporation
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from typing import Any
class Visitor(object):
def defaultVisit(self, node, *args, **kwargs):
raise NotImplementedError
def __getattr__(self, attr):
if attr.startswith("visit"):
return self.defaultVisit
return self.__getattribute__(attr)
def _visitAll(self, iterable, *args, **kwargs):
def filter(x):
return (x is not None) or None
return [filter(x) and accept(x, self, *args, **kwargs) for x in iterable]
# Because of the magic way we add accept methods, mypy does not know they exist
# so this method is important for accept calls to typecheck
def accept(obj: Any, v: Visitor, *args, **kwargs):
return obj._accept(v, *args, **kwargs)