wjones127 commented on code in PR #35568: URL: https://github.com/apache/arrow/pull/35568#discussion_r1225124653
########## python/pyarrow/dataset/protocol.py: ########## @@ -0,0 +1,77 @@ +# 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. +"""Protocol definitions for pyarrow.dataset + +These provide the abstract interface for a dataset. Other libraries may implement +this interface to expose their data, without having to extend PyArrow's classes. + +Applications and libraries that want to consume datasets should accept datasets +that implement these protocols, rather than requiring the specific +PyArrow classes. +""" +from abc import abstractmethod +from typing import Iterator, List, Optional, Protocol + +from pyarrow.dataset import Expression +from pyarrow import Table, IntegerArray, RecordBatch, RecordBatchReader, Schema + + +class Scanner(Protocol): + @abstractmethod + def count_rows(self) -> int: + ... + + @abstractmethod + def head(self, num_rows: int) -> Table: + ... + + @abstractmethod + def take(self, indices: IntegerArray) -> Table: + ... + + @abstractmethod + def to_table(self) -> Table: + ... + + @abstractmethod + def to_batches(self) -> Iterator[RecordBatch]: + ... + + @abstractmethod + def to_reader(self) -> RecordBatchReader: + ... Review Comment: Looking through the code, it seems like it will be the original reader wrapped in some C++ class, but not at all wrapped in Python which is good. I think it's fine if there is Python, but wanted to make sure those that are implemented in Rust or C++ don't have such a limitation. -- 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]
