mingmwang commented on code in PR #3969: URL: https://github.com/apache/arrow-datafusion/pull/3969#discussion_r1006962356
########## datafusion/physical-expr/src/expressions/no_op.rs: ########## @@ -0,0 +1,87 @@ +// 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. + +//! Literal expressions for physical operations + +use std::any::Any; +use std::sync::Arc; + +use arrow::{ + datatypes::{DataType, Schema}, + record_batch::RecordBatch, +}; + +use crate::physical_expr::down_cast_any_ref; +use crate::PhysicalExpr; +use datafusion_common::Result; +use datafusion_expr::ColumnarValue; + +/// A place holder expressions, can not be evaluated +#[derive(Debug, PartialEq, Eq, Default)] +pub struct NoOp {} + +impl NoOp { + /// Create a NoOp expression + pub fn new() -> Self { + Self {} + } +} + +impl std::fmt::Display for NoOp { + fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result { + write!(f, "NoOp") + } +} + +impl PhysicalExpr for NoOp { + /// Return a reference to Any that can be used for downcasting + fn as_any(&self) -> &dyn Any { + self + } + + fn data_type(&self, _input_schema: &Schema) -> Result<DataType> { + Ok(DataType::Null) Review Comment: The `NoOp` expr type will also be used in other places in the following PR. -- 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]
