nu_command/filters/
values.rs

1use indexmap::IndexMap;
2use nu_engine::command_prelude::*;
3
4#[derive(Clone)]
5pub struct Values;
6
7impl Command for Values {
8    fn name(&self) -> &str {
9        "values"
10    }
11
12    fn signature(&self) -> Signature {
13        Signature::build(self.name())
14            .input_output_types(vec![
15                (Type::record(), Type::List(Box::new(Type::Any))),
16                (Type::table(), Type::List(Box::new(Type::Any))),
17            ])
18            .category(Category::Filters)
19    }
20
21    fn description(&self) -> &str {
22        "Given a record or table, produce a list of its columns' values."
23    }
24
25    fn extra_description(&self) -> &str {
26        "This is a counterpart to `columns`, which produces a list of columns' names."
27    }
28
29    fn examples(&self) -> Vec<Example> {
30        vec![
31            Example {
32                example: "{ mode:normal userid:31415 } | values",
33                description: "Get the values from the record (produce a list)",
34                result: Some(Value::list(
35                    vec![Value::test_string("normal"), Value::test_int(31415)],
36                    Span::test_data(),
37                )),
38            },
39            Example {
40                example: "{ f:250 g:191 c:128 d:1024 e:2000 a:16 b:32 } | values",
41                description: "Values are ordered by the column order of the record",
42                result: Some(Value::list(
43                    vec![
44                        Value::test_int(250),
45                        Value::test_int(191),
46                        Value::test_int(128),
47                        Value::test_int(1024),
48                        Value::test_int(2000),
49                        Value::test_int(16),
50                        Value::test_int(32),
51                    ],
52                    Span::test_data(),
53                )),
54            },
55            Example {
56                example: "[[name meaning]; [ls list] [mv move] [cd 'change directory']] | values",
57                description: "Get the values from the table (produce a list of lists)",
58                result: Some(Value::list(
59                    vec![
60                        Value::list(
61                            vec![
62                                Value::test_string("ls"),
63                                Value::test_string("mv"),
64                                Value::test_string("cd"),
65                            ],
66                            Span::test_data(),
67                        ),
68                        Value::list(
69                            vec![
70                                Value::test_string("list"),
71                                Value::test_string("move"),
72                                Value::test_string("change directory"),
73                            ],
74                            Span::test_data(),
75                        ),
76                    ],
77                    Span::test_data(),
78                )),
79            },
80        ]
81    }
82
83    fn run(
84        &self,
85        engine_state: &EngineState,
86        _stack: &mut Stack,
87        call: &Call,
88        input: PipelineData,
89    ) -> Result<PipelineData, ShellError> {
90        let span = call.head;
91        values(engine_state, span, input)
92    }
93}
94
95// The semantics of `values` are as follows:
96// For each column, get the values for that column, in row order.
97// Holes are not preserved, i.e. position in the resulting list
98// does not necessarily equal row number.
99pub fn get_values<'a>(
100    input: impl IntoIterator<Item = &'a Value>,
101    head: Span,
102    input_span: Span,
103) -> Result<Vec<Value>, ShellError> {
104    let mut output: IndexMap<String, Vec<Value>> = IndexMap::new();
105
106    for item in input {
107        match item {
108            Value::Record { val, .. } => {
109                for (k, v) in &**val {
110                    if let Some(vec) = output.get_mut(k) {
111                        vec.push(v.clone());
112                    } else {
113                        output.insert(k.clone(), vec![v.clone()]);
114                    }
115                }
116            }
117            Value::Error { error, .. } => return Err(*error.clone()),
118            _ => {
119                return Err(ShellError::OnlySupportsThisInputType {
120                    exp_input_type: "record or table".into(),
121                    wrong_type: item.get_type().to_string(),
122                    dst_span: head,
123                    src_span: input_span,
124                });
125            }
126        }
127    }
128
129    Ok(output.into_values().map(|v| Value::list(v, head)).collect())
130}
131
132fn values(
133    engine_state: &EngineState,
134    head: Span,
135    input: PipelineData,
136) -> Result<PipelineData, ShellError> {
137    let signals = engine_state.signals().clone();
138    let metadata = input.metadata();
139    match input {
140        PipelineData::Empty => Ok(PipelineData::empty()),
141        PipelineData::Value(v, ..) => {
142            let span = v.span();
143            match v {
144                Value::List { vals, .. } => match get_values(&vals, head, span) {
145                    Ok(cols) => Ok(cols
146                        .into_iter()
147                        .into_pipeline_data_with_metadata(head, signals, metadata)),
148                    Err(err) => Err(err),
149                },
150                Value::Custom { val, .. } => {
151                    let input_as_base_value = val.to_base_value(span)?;
152                    match get_values(&[input_as_base_value], head, span) {
153                        Ok(cols) => Ok(cols
154                            .into_iter()
155                            .into_pipeline_data_with_metadata(head, signals, metadata)),
156                        Err(err) => Err(err),
157                    }
158                }
159                Value::Record { val, .. } => Ok(val
160                    .values()
161                    .cloned()
162                    .collect::<Vec<_>>()
163                    .into_pipeline_data_with_metadata(head, signals, metadata)),
164                // Propagate errors
165                Value::Error { error, .. } => Err(*error),
166                other => Err(ShellError::OnlySupportsThisInputType {
167                    exp_input_type: "record or table".into(),
168                    wrong_type: other.get_type().to_string(),
169                    dst_span: head,
170                    src_span: other.span(),
171                }),
172            }
173        }
174        PipelineData::ListStream(stream, ..) => {
175            let vals: Vec<_> = stream.into_iter().collect();
176            match get_values(&vals, head, head) {
177                Ok(cols) => Ok(cols
178                    .into_iter()
179                    .into_pipeline_data_with_metadata(head, signals, metadata)),
180                Err(err) => Err(err),
181            }
182        }
183        PipelineData::ByteStream(stream, ..) => Err(ShellError::OnlySupportsThisInputType {
184            exp_input_type: "record or table".into(),
185            wrong_type: stream.type_().describe().into(),
186            dst_span: head,
187            src_span: stream.span(),
188        }),
189    }
190}
191
192#[cfg(test)]
193mod test {
194    use super::*;
195
196    #[test]
197    fn test_examples() {
198        use crate::test_examples;
199
200        test_examples(Values {})
201    }
202}
nu_command/filters/values.rs

nu_command/filters/
values.rs
