nu_engine/
column.rs

1use nu_protocol::Value;
2use std::collections::HashSet;
3
4pub fn get_columns(input: &[Value]) -> Vec<String> {
5    let mut columns = vec![];
6    for item in input {
7        let Value::Record { val, .. } = item else {
8            return vec![];
9        };
10
11        for col in val.columns() {
12            if !columns.contains(col) {
13                columns.push(col.to_string());
14            }
15        }
16    }
17
18    columns
19}
20
21// If a column doesn't exist in the input, return it.
22pub fn nonexistent_column<'a, I>(inputs: &[String], columns: I) -> Option<String>
23where
24    I: IntoIterator<Item = &'a String>,
25{
26    let set: HashSet<&String> = HashSet::from_iter(columns);
27
28    for input in inputs {
29        if set.contains(input) {
30            continue;
31        }
32        return Some(input.clone());
33    }
34    None
35}