samredai commented on a change in pull request #4318: URL: https://github.com/apache/iceberg/pull/4318#discussion_r826574111
########## File path: python/src/iceberg/table/schema.py ########## @@ -0,0 +1,346 @@ +# Licensed to the Apache Software Foundation (ASF) under one +# or more contributor license agreements. See the NOTICE file +# distributed with this work for additional information +# regarding copyright ownership. The ASF licenses this file +# to you 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. + +import sys +from typing import Iterable, Tuple + +if sys.version_info >= (3, 8): # pragma: no cover + from typing import Protocol +else: # pragma: no cover + from typing_extensions import Protocol # type: ignore + +if sys.version_info >= (3, 8): # pragma: no cover + from functools import singledispatchmethod +else: # pragma: no cover + from singledispatch import singledispatchmethod # type: ignore + +from iceberg.types import IcebergType, ListType, MapType, NestedField, StructType + + +class SchemaVisitor(Protocol): + def visit(self, node) -> None: # pragma: no cover Review comment: That's right with this current design the visitor doesn't manipulate `node` but it accumulates state as it visits different parts of the schema. I'm wondering if it would be too strict to require concrete visitors to store the state in an attribute specifically called `result` but if that's ok then I can actually make this an ABC class which would enforce it. (A child class would still be allowed to have arguments in addition to `node` if needed): ```py from abc import ABC, abstractmethod class SchemaVisitor(ABC): @abstractmethod def visit(self, node) -> None: ... @property @abstractmethod def result(self): ... ``` Let me know what you think. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
