andygrove commented on a change in pull request #8102: URL: https://github.com/apache/arrow/pull/8102#discussion_r483017698
########## File path: rust/datafusion/src/physical_plan/array_expressions.rs ########## @@ -0,0 +1,106 @@ +// 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. + +//! Array expressions + +use crate::error::{ExecutionError, Result}; +use arrow::array::*; +use arrow::datatypes::DataType; +use std::sync::Arc; + +macro_rules! downcast_vec { + ($ARGS:expr, $ARRAY_TYPE:ident) => {{ + $ARGS + .iter() + .map(|e| match e.as_any().downcast_ref::<$ARRAY_TYPE>() { + Some(array) => Ok(array), + _ => Err(ExecutionError::General("failed to downcast".to_string())), + }) + }}; +} + +macro_rules! array { + ($ARGS:expr, $ARRAY_TYPE:ident, $BUILDER_TYPE:ident) => {{ + // downcast all arguments to their common format + let args = + downcast_vec!($ARGS, $ARRAY_TYPE).collect::<Result<Vec<&$ARRAY_TYPE>>>()?; + + let mut builder = FixedSizeListBuilder::<$BUILDER_TYPE>::new( + <$BUILDER_TYPE>::new(args[0].len()), + args.len() as i32, + ); + // for each entry in the array + for index in 0..args[0].len() { + for arg in &args { + if arg.is_null(index) { + builder.values().append_null()?; + } else { + builder.values().append_value(arg.value(index))?; + } + } + builder.append(true)?; + } + Ok(Arc::new(builder.finish())) + }}; +} + +/// put values in an array. +pub fn array(args: &[ArrayRef]) -> Result<ArrayRef> { + // do not accept 0 arguments. + if args.len() == 0 { + return Err(ExecutionError::InternalError( + "array requires at least one argument".to_string(), + )); + } + + match args[0].data_type() { Review comment: It looks like we assume all values in the list are going to be the same type, which makes sense, but I don't see any validation checks for that. Perhaps we need to add them, or do we expect that type coercion will take care of introducing the appropriate casts? Either way, a specific test for this would be good. ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: [email protected]
