jayzhan211 commented on code in PR #9906: URL: https://github.com/apache/datafusion/pull/9906#discussion_r1618798950
########## datafusion-examples/examples/simplify_udwf_expression.rs: ########## @@ -0,0 +1,142 @@ +// 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. + +use std::any::Any; + +use arrow_schema::DataType; +use datafusion::execution::context::SessionContext; +use datafusion::{error::Result, execution::options::CsvReadOptions}; +use datafusion_expr::function::WindowFunctionSimplification; +use datafusion_expr::{ + expr::WindowFunction, simplify::SimplifyInfo, AggregateFunction, Expr, + PartitionEvaluator, Signature, Volatility, WindowUDF, WindowUDFImpl, +}; + +/// This UDWF will show how to use the WindowUDFImpl::simplify() API +#[derive(Debug, Clone)] +struct SimplifySmoothItUdf { + signature: Signature, +} + +impl SimplifySmoothItUdf { + fn new() -> Self { + Self { + signature: Signature::exact( + // this function will always take one arguments of type f64 + vec![DataType::Float64], + // this function is deterministic and will always return the same + // result for the same input + Volatility::Immutable, + ), + } + } +} +impl WindowUDFImpl for SimplifySmoothItUdf { + fn as_any(&self) -> &dyn Any { + self + } + + fn name(&self) -> &str { + "simplify_smooth_it" + } + + fn signature(&self) -> &Signature { + &self.signature + } + + fn return_type(&self, _arg_types: &[DataType]) -> Result<DataType> { + Ok(DataType::Float64) + } + + fn partition_evaluator(&self) -> Result<Box<dyn PartitionEvaluator>> { + todo!() + } + + /// this function will simplify `SimplifySmoothItUdf` to `SmoothItUdf`. + fn simplify(&self) -> Option<WindowFunctionSimplification> { + // Ok(ExprSimplifyResult::Simplified(Expr::WindowFunction( Review Comment: remind to cleanup this -- 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: github-unsubscr...@datafusion.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For additional commands, e-mail: github-h...@datafusion.apache.org
