risingwave_expr_impl/scalar/
string_to_array.rs

1// Copyright 2025 RisingWave Labs
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15use auto_enums::auto_enum;
16use risingwave_common::array::{ListValue, Utf8Array};
17use risingwave_expr::function;
18
19#[auto_enum(Iterator)]
20fn string_to_array_inner<'a>(s: &'a str, sep: Option<&'a str>) -> impl Iterator<Item = &'a str> {
21    match s.is_empty() {
22        true => std::iter::empty(),
23        #[nested]
24        _ => match sep {
25            Some(sep) if sep.is_empty() => std::iter::once(s),
26            Some(sep) => s.split(sep),
27            None => s.char_indices().map(move |(index, ch)| {
28                let len = ch.len_utf8();
29                &s[index..index + len]
30            }),
31        },
32    }
33}
34
35// Use cases shown in `e2e_test/batch/functions/string_to_array.slt.part`
36#[function("string_to_array(varchar, varchar) -> varchar[]")]
37pub fn string_to_array2(s: &str, sep: Option<&str>) -> ListValue {
38    ListValue::new(string_to_array_inner(s, sep).collect::<Utf8Array>().into())
39}
40
41#[function("string_to_array(varchar, varchar, varchar) -> varchar[]")]
42pub fn string_to_array3(s: &str, sep: Option<&str>, null: Option<&str>) -> ListValue {
43    let Some(null) = null else {
44        return string_to_array2(s, sep);
45    };
46    ListValue::new(
47        string_to_array_inner(s, sep)
48            .map(|x| if x == null { None } else { Some(x) })
49            .collect::<Utf8Array>()
50            .into(),
51    )
52}
risingwave_expr_impl/scalar/string_to_array.rs

risingwave_expr_impl/scalar/
string_to_array.rs
