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 Reverse;
impl Command for Reverse {
fn name(&self) -> &str {
"reverse"
}
fn signature(&self) -> nu_protocol::Signature {
Signature::build("reverse")
.input_output_types(vec![
(
Type::List(Box::new(Type::Any)),
Type::List(Box::new(Type::Any)),
),
(Type::Table(vec![]), Type::Table(vec![])),
])
.category(Category::Filters)
}
fn usage(&self) -> &str {
"Reverses the input list or table."
}
fn search_terms(&self) -> Vec<&str> {
vec!["convert, inverse, flip"]
}
fn examples(&self) -> Vec<Example> {
vec![
Example {
example: "[0,1,2,3] | reverse",
description: "Reverse a list",
result: Some(Value::List {
vals: vec![
Value::test_int(3),
Value::test_int(2),
Value::test_int(1),
Value::test_int(0),
],
span: Span::test_data(),
}),
},
Example {
example: "[{a: 1} {a: 2}] | reverse",
description: "Reverse a table",
result: Some(Value::List {
vals: vec![
Value::test_record(vec!["a"], vec![Value::test_int(2)]),
Value::test_record(vec!["a"], vec![Value::test_int(1)]),
],
span: Span::test_data(),
}),
},
]
}
fn run(
&self,
engine_state: &EngineState,
_stack: &mut Stack,
call: &Call,
input: PipelineData,
) -> Result<PipelineData, ShellError> {
let metadata = input.metadata();
#[allow(clippy::needless_collect)]
let v: Vec<_> = input.into_iter_strict(call.head)?.collect();
let iter = v.into_iter().rev();
Ok(iter
.into_pipeline_data(engine_state.ctrlc.clone())
.set_metadata(metadata))
}
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn test_examples() {
use crate::test_examples;
test_examples(Reverse {})
}
}