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_list(vec![Value::test_record(record!(
"b" => Value::test_string("value"),
))]),
)),
Value::test_record(record!(
"a" => Value::test_list(vec![Value::test_record(record!(
"b" => Value::test_string("value"),
))]),
)),
])),
},
]
}
}
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)?;
match input {
PipelineData::Value(Value::Error { error, .. }, ..) => Err(*error),
PipelineData::Value(mut value, metadata) => {
if let Value::Closure { val, .. } = replacement {
match (cell_path.members.first(), &mut value) {
(Some(PathMember::String { .. }), Value::List { vals, .. }) => {
let mut closure = ClosureEval::new(engine_state, stack, *val);
for val in vals {
insert_value_by_closure(
val,
&mut closure,
head,
&cell_path.members,
false,
)?;
}
}
(first, _) => {
insert_single_value_by_closure(
&mut value,
ClosureEvalOnce::new(engine_state, stack, *val),
head,
&cell_path.members,
matches!(first, Some(PathMember::Int { .. })),
)?;
}
}
} else {
value.insert_data_at_cell_path(&cell_path.members, replacement, head)?;
}
Ok(value.into_pipeline_data_with_metadata(metadata))
}
PipelineData::ListStream(stream, metadata) => {
if let Some((
&PathMember::Int {
val,
span: path_span,
..
},
path,
)) = cell_path.members.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));
let new_value = ClosureEvalOnce::new(engine_state, stack, *val)
.run_with_value(value.clone())?
.into_value(head)?;
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,
path,
true,
)?;
} else {
value.insert_data_at_cell_path(path, replacement, head)?;
}
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,
engine_state.signals().clone(),
metadata,
))
} else if let Value::Closure { val, .. } = replacement {
let mut closure = ClosureEval::new(engine_state, stack, *val);
let stream = stream.map(move |mut value| {
let err = insert_value_by_closure(
&mut value,
&mut closure,
head,
&cell_path.members,
false,
);
if let Err(e) = err {
Value::error(e, head)
} else {
value
}
});
Ok(PipelineData::ListStream(stream, metadata))
} else {
let stream = stream.map(move |mut value| {
if let Err(e) = value.insert_data_at_cell_path(
&cell_path.members,
replacement.clone(),
head,
) {
Value::error(e, head)
} else {
value
}
});
Ok(PipelineData::ListStream(stream, metadata))
}
}
PipelineData::Empty => Err(ShellError::IncompatiblePathAccess {
type_name: "empty pipeline".to_string(),
span: head,
}),
PipelineData::ByteStream(stream, ..) => Err(ShellError::IncompatiblePathAccess {
type_name: stream.type_().describe().into(),
span: head,
}),
}
}
fn insert_value_by_closure(
value: &mut Value,
closure: &mut ClosureEval,
span: Span,
cell_path: &[PathMember],
first_path_member_int: bool,
) -> Result<(), ShellError> {
let value_at_path = if first_path_member_int {
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(value_at_path)?.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],
first_path_member_int: bool,
) -> Result<(), ShellError> {
let value_at_path = if first_path_member_int {
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(value_at_path)?.into_value(span)?;
value.insert_data_at_cell_path(cell_path, new_value, span)
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn test_examples() {
use crate::test_examples;
test_examples(Insert {})
}
}