use std::borrow::Cow;
use nu_engine::{ClosureEval, ClosureEvalOnce, command_prelude::*};
use nu_protocol::ast::PathMember;
#[derive(Clone)]
pub struct Insert;
impl Command for Insert {
fn name(&self) -> &str {
"insert"
}
fn signature(&self) -> Signature {
Signature::build("insert")
.input_output_types(vec![
(Type::record(), Type::record()),
(Type::table(), Type::table()),
(
Type::List(Box::new(Type::Any)),
Type::List(Box::new(Type::Any)),
),
])
.required(
"field",
SyntaxShape::CellPath,
"The name of the column to insert.",
)
.required(
"new value",
SyntaxShape::Any,
"The new value to give the cell(s).",
)
.allow_variants_without_examples(true)
.category(Category::Filters)
}
fn description(&self) -> &str {
"Insert a new column, using an expression or closure to create each row's values."
}
fn extra_description(&self) -> &str {
"When inserting a column, the closure will be run for each row, and the current row will be passed as the first argument.
When inserting into a specific index, the closure will instead get the current value at the index or null if inserting at the end of a list/table."
}
fn search_terms(&self) -> Vec<&str> {
vec!["add"]
}
fn run(
&self,
engine_state: &EngineState,
stack: &mut Stack,
call: &Call,
input: PipelineData,
) -> Result<PipelineData, ShellError> {
insert(engine_state, stack, call, input)
}
fn examples(&self) -> Vec<Example<'_>> {
vec![
Example {
description: "Insert a new entry into a single record",
example: "{'name': 'nu', 'stars': 5} | insert alias 'Nushell'",
result: Some(Value::test_record(record! {
"name" => Value::test_string("nu"),
"stars" => Value::test_int(5),
"alias" => Value::test_string("Nushell"),
})),
},
Example {
description: "Insert a new column into a table, populating all rows",
example: "[[project, lang]; ['Nushell', 'Rust']] | insert type 'shell'",
result: Some(Value::test_list(vec![Value::test_record(record! {
"project" => Value::test_string("Nushell"),
"lang" => Value::test_string("Rust"),
"type" => Value::test_string("shell"),
})])),
},
Example {
description: "Insert a new column with values computed based off the other columns",
example: "[[foo]; [7] [8] [9]] | insert bar {|row| $row.foo * 2 }",
result: Some(Value::test_list(vec![
Value::test_record(record! {
"foo" => Value::test_int(7),
"bar" => Value::test_int(14),
}),
Value::test_record(record! {
"foo" => Value::test_int(8),
"bar" => Value::test_int(16),
}),
Value::test_record(record! {
"foo" => Value::test_int(9),
"bar" => Value::test_int(18),
}),
])),
},
Example {
description: "Insert a new value into a list at an index",
example: "[1 2 4] | insert 2 3",
result: Some(Value::test_list(vec![
Value::test_int(1),
Value::test_int(2),
Value::test_int(3),
Value::test_int(4),
])),
},
Example {
description: "Insert a new value at the end of a list",
example: "[1 2 3] | insert 3 4",
result: Some(Value::test_list(vec![
Value::test_int(1),
Value::test_int(2),
Value::test_int(3),
Value::test_int(4),
])),
},
Example {
description: "Insert into a nested path, creating new values as needed",
example: "[{} {a: [{}]}] | insert a.0.b \"value\"",
result: Some(Value::test_list(vec![
Value::test_record(record!(
"a" => Value::test_record(record!(
"b" => Value::test_string("value"),
)),
)),
Value::test_record(record!(
"a" => Value::test_list(vec![Value::test_record(record!(
))]),
)),
])),
},
]
}
}
fn insert_recursive(
engine_state: &EngineState,
stack: &mut Stack,
head_span: Span,
replacement: Value,
input: PipelineData,
cell_paths: &[PathMember],
) -> Result<PipelineData, ShellError> {
match input {
PipelineData::Value(Value::Error { error, .. }, ..) => Err(*error),
PipelineData::Value(mut value, metadata) => {
if let Value::Closure { val, .. } = replacement {
insert_single_value_by_closure(
&mut value,
ClosureEvalOnce::new(engine_state, stack, *val),
head_span,
cell_paths,
false,
)?;
} else {
value.insert_data_at_cell_path(cell_paths, replacement, head_span)?;
}
Ok(value.into_pipeline_data_with_metadata(metadata))
}
PipelineData::ListStream(stream, metadata) => {
if let Some((
&PathMember::Int {
val,
span: path_span,
..
},
path,
)) = cell_paths.split_first()
{
let mut stream = stream.into_iter();
let mut pre_elems = vec![];
for idx in 0..val {
if let Some(v) = stream.next() {
pre_elems.push(v);
} else {
return Err(ShellError::InsertAfterNextFreeIndex {
available_idx: idx,
span: path_span,
});
}
}
if path.is_empty() {
if let Value::Closure { val, .. } = replacement {
let value = stream.next();
let end_of_stream = value.is_none();
let value = value.unwrap_or(Value::nothing(head_span));
let new_value = ClosureEvalOnce::new(engine_state, stack, *val)
.run_with_value(value.clone())?
.into_value(head_span)?;
pre_elems.push(new_value);
if !end_of_stream {
pre_elems.push(value);
}
} else {
pre_elems.push(replacement);
}
} else if let Some(mut value) = stream.next() {
if let Value::Closure { val, .. } = replacement {
insert_single_value_by_closure(
&mut value,
ClosureEvalOnce::new(engine_state, stack, *val),
head_span,
path,
true,
)?;
} else {
value.insert_data_at_cell_path(path, replacement, head_span)?;
}
pre_elems.push(value)
} else {
return Err(ShellError::AccessBeyondEnd {
max_idx: pre_elems.len() - 1,
span: path_span,
});
}
Ok(pre_elems
.into_iter()
.chain(stream)
.into_pipeline_data_with_metadata(
head_span,
engine_state.signals().clone(),
metadata,
))
} else if let Some(new_cell_paths) = Value::try_put_int_path_member_on_top(cell_paths) {
insert_recursive(
engine_state,
stack,
head_span,
replacement,
PipelineData::ListStream(stream, metadata),
&new_cell_paths,
)
} else if let Value::Closure { val, .. } = replacement {
let mut closure = ClosureEval::new(engine_state, stack, *val);
let cell_paths = cell_paths.to_vec();
let stream = stream.map(move |mut value| {
let err =
insert_value_by_closure(&mut value, &mut closure, head_span, &cell_paths);
if let Err(e) = err {
Value::error(e, head_span)
} else {
value
}
});
Ok(PipelineData::list_stream(stream, metadata))
} else {
let cell_paths = cell_paths.to_vec();
let stream = stream.map(move |mut value| {
if let Err(e) =
value.insert_data_at_cell_path(&cell_paths, replacement.clone(), head_span)
{
Value::error(e, head_span)
} else {
value
}
});
Ok(PipelineData::list_stream(stream, metadata))
}
}
PipelineData::Empty => Err(ShellError::IncompatiblePathAccess {
type_name: "empty pipeline".to_string(),
span: head_span,
}),
PipelineData::ByteStream(stream, ..) => Err(ShellError::IncompatiblePathAccess {
type_name: stream.type_().describe().into(),
span: head_span,
}),
}
}
fn insert(
engine_state: &EngineState,
stack: &mut Stack,
call: &Call,
input: PipelineData,
) -> Result<PipelineData, ShellError> {
let head = call.head;
let cell_path: CellPath = call.req(engine_state, stack, 0)?;
let replacement: Value = call.req(engine_state, stack, 1)?;
let input = input.into_stream_or_original(engine_state);
insert_recursive(
engine_state,
stack,
head,
replacement,
input,
&cell_path.members,
)
}
fn insert_value_by_closure(
value: &mut Value,
closure: &mut ClosureEval,
span: Span,
cell_path: &[PathMember],
) -> Result<(), ShellError> {
let new_value = closure.run_with_value(value.clone())?.into_value(span)?;
value.insert_data_at_cell_path(cell_path, new_value, span)
}
fn insert_single_value_by_closure(
value: &mut Value,
closure: ClosureEvalOnce,
span: Span,
cell_path: &[PathMember],
cell_value_as_arg: bool,
) -> Result<(), ShellError> {
let arg = if cell_value_as_arg {
value
.follow_cell_path(cell_path)
.map(Cow::into_owned)
.unwrap_or(Value::nothing(span))
} else {
value.clone()
};
let new_value = closure.run_with_value(arg)?.into_value(span)?;
value.insert_data_at_cell_path(cell_path, new_value, span)
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn test_examples() -> nu_test_support::Result {
nu_test_support::test().examples(Insert)
}
}