// Copyright 2023 RisingWave Labs
//
// Licensed 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 risingwave_common::array::ListRef;
use risingwave_common::types::ScalarRefImpl;
use risingwave_expr::function;

#[function(
    "unnest(anyarray) -> setof any",
    type_infer = "|args| Ok(args[0].unnest_list().clone())"
)]
fn unnest(list: ListRef<'_>) -> impl Iterator<Item = Option<ScalarRefImpl<'_>>> {
    list.flatten().iter()
}
