Add values command (see #7166) (#7583)

crates/nu-command/src/default_context.rs

@@ -138,6 +138,7 @@ pub fn create_default_context() -> EngineState {
             Upsert,
             Update,
             UpdateCells,
+            Values,
             Where,
             Window,
             Wrap,

crates/nu-command/src/example_test.rs

@@ -9,8 +9,9 @@ pub fn test_examples(cmd: impl Command + 'static) {
 #[cfg(test)]
 mod test_examples {
     use super::super::{
-        Ansi, Date, Echo, From, If, Into, Let, LetEnv, Math, MathEuler, MathPi, MathRound, Path,
+        Ansi, Date, Echo, From, If, Into, IntoString, Let, LetEnv, Math, MathEuler, MathPi,
-        Random, Split, SplitColumn, SplitRow, Str, StrJoin, StrLength, StrReplace, Url, Wrap,
+        MathRound, Path, Random, Split, SplitColumn, SplitRow, Str, StrJoin, StrLength, StrReplace,
+        Url, Values, Wrap,
     };
     use crate::{Break, Mut, To};
     use itertools::Itertools;
@@ -69,6 +70,7 @@ mod test_examples {
             working_set.add_decl(Box::new(If));
             working_set.add_decl(Box::new(To));
             working_set.add_decl(Box::new(Into));
+            working_set.add_decl(Box::new(IntoString));
             working_set.add_decl(Box::new(Random));
             working_set.add_decl(Box::new(Split));
             working_set.add_decl(Box::new(SplitColumn));
@@ -77,6 +79,7 @@ mod test_examples {
             working_set.add_decl(Box::new(Path));
             working_set.add_decl(Box::new(Date));
             working_set.add_decl(Box::new(Url));
+            working_set.add_decl(Box::new(Values));
             working_set.add_decl(Box::new(Ansi));
             working_set.add_decl(Box::new(Wrap));
             working_set.add_decl(Box::new(LetEnv));

crates/nu-command/src/filters/columns.rs

@@ -24,7 +24,11 @@ impl Command for Columns {
     }
 
     fn usage(&self) -> &str {
-        "Show the columns in the input."
+        "Given a record or table, produce a list of its columns' names."
+    }
+
+    fn extra_usage(&self) -> &str {
+        "This is a counterpart to `values`, which produces a list of columns' values."
     }
 
     fn examples(&self) -> Vec<Example> {

crates/nu-command/src/filters/each.rs

@@ -73,20 +73,29 @@ with 'transpose' first."#
         vec![
             Example {
                 example: "[1 2 3] | each {|e| 2 * $e }",
-                description: "Multiplies elements in list",
+                description: "Multiplies elements in the list",
                 result: Some(Value::List {
                     vals: stream_test_1,
                     span: Span::test_data(),
                 }),
             },
+            Example {
+                example: "{major:2, minor:1, patch:4} | values | each { into string }",
+                description: "Produce a list of values in the record, converted to string",
+                result: Some(Value::List {
+                    vals: vec![
+                        Value::test_string("2"),
+                        Value::test_string("1"),
+                        Value::test_string("4"),
+                    ],
+                    span: Span::test_data(),
+                }),
+            },
             Example {
                 example: r#"[1 2 3 2] | each {|e| if $e == 2 { "two" } }"#,
                 description: "Produce a list that has \"two\" for each 2 in the input",
                 result: Some(Value::List {
-                    vals: vec![
+                    vals: vec![Value::test_string("two"), Value::test_string("two")],
-                        Value::string("two", Span::test_data()),
-                        Value::string("two", Span::test_data()),
-                    ],
                     span: Span::test_data(),
                 }),
             },

crates/nu-command/src/filters/mod.rs

@@ -47,6 +47,7 @@ mod update;
 mod update_cells;
 mod upsert;
 mod utils;
+mod values;
 mod where_;
 mod window;
 mod wrap;
@@ -100,6 +101,7 @@ pub use uniq_by::UniqBy;
 pub use update::Update;
 pub use update_cells::UpdateCells;
 pub use upsert::Upsert;
+pub use values::Values;
 pub use where_::Where;
 pub use window::Window;
 pub use wrap::Wrap;

crates/nu-command/src/filters/transpose.rs

@@ -274,7 +274,7 @@ pub fn transpose(
                                 }
                                 v => Value::List {
                                     vals: vec![v.clone(), x.clone()],
-                                    span: v.span().expect("this should be a valid span"),
+                                    span: v.expect_span(),
                                 },
                             };
                             cols.remove(index);
@@ -313,7 +313,7 @@ pub fn transpose(
                                 }
                                 v => Value::List {
                                     vals: vec![v.clone(), Value::nothing(name)],
-                                    span: v.span().expect("this should be a valid span"),
+                                    span: v.expect_span(),
                                 },
                             };
                             cols.remove(index);

crates/nu-command/src/filters/values.rs

@@ -0,0 +1,213 @@
+use indexmap::IndexMap;
+use nu_protocol::ast::Call;
+use nu_protocol::engine::{Command, EngineState, Stack};
+use nu_protocol::{
+    Category, Example, IntoInterruptiblePipelineData, PipelineData, ShellError, Signature, Span,
+    Type, Value,
+};
+
+#[derive(Clone)]
+pub struct Values;
+
+impl Command for Values {
+    fn name(&self) -> &str {
+        "values"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build(self.name())
+            .input_output_types(vec![
+                (Type::Record(vec![]), Type::List(Box::new(Type::Any))),
+                (Type::Table(vec![]), Type::List(Box::new(Type::Any))),
+            ])
+            .category(Category::Filters)
+    }
+
+    fn usage(&self) -> &str {
+        "Given a record or table, produce a list of its columns' values."
+    }
+
+    fn extra_usage(&self) -> &str {
+        "This is a counterpart to `columns`, which produces a list of columns' names."
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                example: "{ mode:normal userid:31415 } | values",
+                description: "Get the values from the record (produce a list)",
+                result: Some(Value::List {
+                    vals: vec![Value::test_string("normal"), Value::test_int(31415)],
+                    span: Span::test_data(),
+                }),
+            },
+            Example {
+                example: "{ f:250 g:191 c:128 d:1024 e:2000 a:16 b:32 } | values",
+                description: "Values are ordered by the column order of the record",
+                result: Some(Value::List {
+                    vals: vec![
+                        Value::test_int(250),
+                        Value::test_int(191),
+                        Value::test_int(128),
+                        Value::test_int(1024),
+                        Value::test_int(2000),
+                        Value::test_int(16),
+                        Value::test_int(32),
+                    ],
+                    span: Span::test_data(),
+                }),
+            },
+            Example {
+                example: "[[name meaning]; [ls list] [mv move] [cd 'change directory']] | values",
+                description: "Get the values from the table (produce a list of lists)",
+                result: Some(Value::List {
+                    vals: vec![
+                        Value::List {
+                            vals: vec![
+                                Value::test_string("ls"),
+                                Value::test_string("mv"),
+                                Value::test_string("cd"),
+                            ],
+                            span: Span::test_data(),
+                        },
+                        Value::List {
+                            vals: vec![
+                                Value::test_string("list"),
+                                Value::test_string("move"),
+                                Value::test_string("change directory"),
+                            ],
+                            span: Span::test_data(),
+                        },
+                    ],
+                    span: Span::test_data(),
+                }),
+            },
+        ]
+    }
+
+    fn run(
+        &self,
+        engine_state: &EngineState,
+        _stack: &mut Stack,
+        call: &Call,
+        input: PipelineData,
+    ) -> Result<PipelineData, ShellError> {
+        let span = call.head;
+        values(engine_state, span, input)
+    }
+}
+
+// The semantics of `values` are as follows:
+// For each column, get the values for that column, in row order.
+// Holes are not preserved, i.e. position in the resulting list
+// does not necessarily equal row number.
+pub fn get_values<'a>(
+    input: impl IntoIterator<Item = &'a Value>,
+    head: Span,
+    input_span: Span,
+) -> Result<Vec<Value>, ShellError> {
+    let mut output: IndexMap<String, Vec<Value>> = IndexMap::new();
+
+    for item in input {
+        match item {
+            Value::Record { cols, vals, .. } => {
+                for (k, v) in cols.iter().zip(vals.iter()) {
+                    if let Some(vec) = output.get_mut(k) {
+                        vec.push(v.clone());
+                    } else {
+                        output.insert(k.clone(), vec![v.clone()]);
+                    }
+                }
+            }
+            Value::Error { error } => return Err(error.clone()),
+            _ => {
+                return Err(ShellError::OnlySupportsThisInputType(
+                    "record or table".into(),
+                    item.get_type().to_string(),
+                    head,
+                    input_span,
+                ))
+            }
+        }
+    }
+
+    Ok(output.into_values().map(|v| Value::list(v, head)).collect())
+}
+
+fn values(
+    engine_state: &EngineState,
+    head: Span,
+    input: PipelineData,
+) -> Result<PipelineData, ShellError> {
+    let ctrlc = engine_state.ctrlc.clone();
+    let metadata = input.metadata();
+    match input {
+        PipelineData::Empty => Ok(PipelineData::Empty),
+        PipelineData::Value(Value::List { vals, span }, ..) => {
+            match get_values(&vals, head, span) {
+                Ok(cols) => Ok(cols
+                    .into_iter()
+                    .into_pipeline_data(ctrlc)
+                    .set_metadata(metadata)),
+                Err(err) => Err(err),
+            }
+        }
+        PipelineData::Value(Value::CustomValue { val, span }, ..) => {
+            let input_as_base_value = val.to_base_value(span)?;
+            match get_values(&[input_as_base_value], head, span) {
+                Ok(cols) => Ok(cols
+                    .into_iter()
+                    .into_pipeline_data(ctrlc)
+                    .set_metadata(metadata)),
+                Err(err) => Err(err),
+            }
+        }
+        PipelineData::ListStream(stream, ..) => {
+            let vals: Vec<_> = stream.into_iter().collect();
+            match get_values(&vals, head, head) {
+                Ok(cols) => Ok(cols
+                    .into_iter()
+                    .into_pipeline_data(ctrlc)
+                    .set_metadata(metadata)),
+                Err(err) => Err(err),
+            }
+        }
+        PipelineData::Value(Value::Record { vals, .. }, ..) => {
+            Ok(vals.into_pipeline_data(ctrlc).set_metadata(metadata))
+        }
+        // Propagate errors
+        PipelineData::Value(Value::Error { error: _ }, ..) => Ok(input),
+        PipelineData::Value(other, ..) => {
+            Err(ShellError::OnlySupportsThisInputType(
+                "record or table".into(),
+                other.get_type().to_string(),
+                head,
+                // This line requires the Value::Error match above.
+                other.expect_span(),
+            ))
+        }
+        PipelineData::ExternalStream { .. } => {
+            Err(ShellError::OnlySupportsThisInputType(
+                "record or table".into(),
+                "raw data".into(),
+                head,
+                // This line requires the PipelineData::Empty and PipelineData::ListStream matches above.
+                input
+                    .span()
+                    .expect("PipelineData::ExternalStream had no span"),
+            ))
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_examples() {
+        use crate::test_examples;
+
+        test_examples(Values {})
+    }
+}

crates/nu-command/src/platform/ansi/ansi_.rs

@@ -723,7 +723,7 @@ Format: #
                     _ => {
                         return Err(ShellError::IncompatibleParametersSingle(
                             format!("problem with key: {}", k),
-                            code.span().expect("error with span"),
+                            code.expect_span(),
                         ))
                     }
                 }

crates/nu-command/src/viewers/table.rs

@@ -654,7 +654,7 @@ fn handle_row_stream(
                 ctrlc,
             )
         }
-        // Next, `into html -l` sources:
+        // Next, `to html -l` sources:
         Some(PipelineMetadata {
             data_source: DataSource::HtmlThemes,
         }) => {

crates/nu-engine/src/column.rs

@@ -5,7 +5,7 @@ pub fn get_columns<'a>(input: impl IntoIterator<Item = &'a Value>) -> Vec<String
     let mut columns = vec![];
 
     for item in input {
-        if let Value::Record { cols, vals: _, .. } = item {
+        if let Value::Record { cols, .. } = item {
             for col in cols {
                 if !columns.contains(col) {
                     columns.push(col.to_string());

src/tests/test_engine.rs

@@ -53,7 +53,7 @@ fn in_and_if_else() -> TestResult {
 
 #[test]
 fn help_works_with_missing_requirements() -> TestResult {
-    run_test(r#"each --help | lines | length"#, "40")
+    run_test(r#"each --help | lines | length"#, "43")
 }
 
 #[test]