jcsherin commented on code in PR #13040: URL: https://github.com/apache/datafusion/pull/13040#discussion_r1815182917
########## datafusion/functions-window/src/ntile.rs: ########## @@ -0,0 +1,192 @@ +// 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 std::fmt::Debug; +use std::sync::{Arc, OnceLock}; + +use crate::utils::{get_scalar_value_from_args, get_unsigned_integer}; +use datafusion_common::arrow::array::{ArrayRef, UInt64Array}; +use datafusion_common::arrow::datatypes::{DataType, Field}; +use datafusion_common::{exec_err, DataFusionError, Result, ScalarValue}; +use datafusion_expr::window_doc_sections::DOC_SECTION_RANKING; +use datafusion_expr::{ + Documentation, Literal, PartitionEvaluator, Signature, Volatility, WindowUDFImpl, +}; +use datafusion_functions_window_common::expr::ExpressionArgs; +use datafusion_functions_window_common::field; +use datafusion_functions_window_common::partition::PartitionEvaluatorArgs; +use datafusion_physical_expr_common::physical_expr::PhysicalExpr; +use field::WindowUDFFieldArgs; + +get_or_init_udwf!( + Ntile, + ntile, + "integer ranging from 1 to the argument value, dividing the partition as equally as possible" +); + +pub fn ntile(arg: i64) -> datafusion_expr::Expr { + ntile_udwf().call(vec![arg.lit()]) +} + +#[derive(Debug)] +pub struct Ntile { + signature: Signature, +} + +impl Ntile { + /// Create a new `ntile` function + pub fn new() -> Self { + Self { + signature: Signature::uniform( + 1, + vec![ + DataType::UInt64, + DataType::UInt32, + DataType::UInt16, + DataType::UInt8, + DataType::Int64, + DataType::Int32, + DataType::Int16, + DataType::Int8, + ], + Volatility::Immutable, + ), + } + } +} + +impl Default for Ntile { + fn default() -> Self { + Self::new() + } +} + +static DOCUMENTATION: OnceLock<Documentation> = OnceLock::new(); + +fn get_ntile_doc() -> &'static Documentation { + DOCUMENTATION.get_or_init(|| { + Documentation::builder() + .with_doc_section(DOC_SECTION_RANKING) + .with_description( + "Integer ranging from 1 to the argument value, dividing the partition as equally as possible", + ) + .with_syntax_example("ntile(expression)") + .with_argument("expression","An integer describing the number groups the partition should be split into") + .build() + .unwrap() + }) +} + +impl WindowUDFImpl for Ntile { + fn as_any(&self) -> &dyn Any { + self + } + + fn name(&self) -> &str { + "ntile" + } + + fn signature(&self) -> &Signature { + &self.signature + } + + fn expressions(&self, expr_args: ExpressionArgs) -> Vec<Arc<dyn PhysicalExpr>> { + parse_expr(expr_args.input_exprs(), expr_args.input_types()) + .into_iter() + .collect::<Vec<_>>() + } Review Comment: I think you can remove this completely and rely on the default implementation for `ntile`. From what I see `ntile` doesn't depend on the input expression in partition evaluator. This implementation is required in `lead/lag` because it is possible that it can be called with `NULL` (input expression), and we try to deduce the type for that `NULL` if a default value argument exists. For `lead/lag` the types of the input expression and the default value needs to be the same in partition evaluator. -- 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
