alamb commented on code in PR #9113: URL: https://github.com/apache/arrow-datafusion/pull/9113#discussion_r1476467729
########## datafusion/functions-array/src/macros.rs: ########## @@ -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. + +/// Creates external API functions for an array UDF. Specifically, creates +/// +/// 1. Single `ScalarUDF` instance +/// +/// Creates a singleton `ScalarUDF` of the `$UDF` function named `$GNAME` and a +/// function named `$NAME` which returns that function named $NAME. +/// +/// This is used to ensure creating the list of `ScalarUDF` only happens once. +/// +/// # 2. `expr_fn` style function +/// +/// These are functions that create an `Expr` that invokes the UDF, used +/// primarily to programmatically create expressions. +/// +/// For example: +/// ```text +/// pub fn array_to_string(delimiter: Expr) -> Expr { +/// ... +/// } +/// ``` +/// # Arguments +/// * `UDF`: name of the [`ScalarUDFImpl`] +/// * `EXPR_FN`: name of the expr_fn function to be created +/// * `arg`: 0 or more named arguments for the function +/// * `DOC`: documentation string for the function +/// * `SCALAR_UDF_FUNC`: name of the function to create (just) the `ScalarUDF` +/// * `GNAME`: name for the single static instance of the `ScalarUDF` +macro_rules! make_udf_function { Review Comment: I should have mentioned that -- there is some version of this macro in the `datafusion-functions` crate - https://github.com/apache/arrow-datafusion/blob/main/datafusion/functions/src/macros.rs However it isn't quite the same (as the feature flag is on the entire `datafusion-functions-array` crate rather than on subsets of functions) My thinking was that we would only have 2 function crates -- `datatfusion_functions` and `datafusion_functions_arrays` and thus the replication was ok We could potentially move the macros into datafusion_expr or datafusion_common perhaps 🤔 -- 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]
