nushell/crates/nu-cli/src/commands/reverse.rs
2020-06-13 16:03:39 +12:00

69 lines
1.7 KiB
Rust

use crate::commands::WholeStreamCommand;
use crate::context::CommandRegistry;
use crate::prelude::*;
use nu_errors::ShellError;
use nu_protocol::{ReturnSuccess, Signature, UntaggedValue};
pub struct Reverse;
#[async_trait]
impl WholeStreamCommand for Reverse {
fn name(&self) -> &str {
"reverse"
}
fn signature(&self) -> Signature {
Signature::build("reverse")
}
fn usage(&self) -> &str {
"Reverses the table."
}
async fn run(
&self,
args: CommandArgs,
registry: &CommandRegistry,
) -> Result<OutputStream, ShellError> {
reverse(args, registry).await
}
fn examples(&self) -> Vec<Example> {
vec![Example {
description: "Sort list of numbers in descending file size",
example: "echo [3 1 2 19 0] | reverse",
result: Some(vec![
UntaggedValue::int(0).into(),
UntaggedValue::int(19).into(),
UntaggedValue::int(2).into(),
UntaggedValue::int(1).into(),
UntaggedValue::int(3).into(),
]),
}]
}
}
async fn reverse(
args: CommandArgs,
registry: &CommandRegistry,
) -> Result<OutputStream, ShellError> {
let registry = registry.clone();
let args = args.evaluate_once(&registry).await?;
let (input, _args) = args.parts();
let input = input.collect::<Vec<_>>().await;
Ok(futures::stream::iter(input.into_iter().rev().map(ReturnSuccess::value)).to_output_stream())
}
#[cfg(test)]
mod tests {
use super::Reverse;
#[test]
fn examples_work_as_expected() {
use crate::examples::test as test_examples;
test_examples(Reverse {})
}
}