nushell/crates/nu-cli/src/commands/shuffle.rs

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use crate::commands::WholeStreamCommand;
use crate::context::CommandRegistry;
use crate::prelude::*;
use nu_errors::ShellError;
use nu_protocol::{ReturnSuccess, ReturnValue, Signature, SyntaxShape, Value};
use nu_source::Tagged;
use rand::seq::SliceRandom;
use rand::thread_rng;
pub struct Shuffle;
#[derive(Deserialize)]
pub struct Arguments {
#[serde(rename = "num")]
limit: Option<Tagged<u64>>,
}
impl WholeStreamCommand for Shuffle {
fn name(&self) -> &str {
"shuffle"
}
fn signature(&self) -> Signature {
Signature::build("shuffle").named(
"num",
SyntaxShape::Int,
"Limit `num` number of rows",
Some('n'),
)
}
fn usage(&self) -> &str {
"Shuffle rows randomly."
}
fn run(
&self,
args: CommandArgs,
registry: &CommandRegistry,
) -> Result<OutputStream, ShellError> {
args.process(registry, shuffle)?.run()
}
}
fn shuffle(
Arguments { limit }: Arguments,
RunnableContext { input, .. }: RunnableContext,
) -> Result<OutputStream, ShellError> {
let stream = async_stream! {
let mut values: Vec<Value> = input.collect().await;
let out = if let Some(n) = limit {
let (shuffled, _) = values.partial_shuffle(&mut thread_rng(), *n as usize);
shuffled.to_vec()
} else {
values.shuffle(&mut thread_rng());
values.clone()
};
for val in out.into_iter() {
yield ReturnSuccess::value(val);
}
};
let stream: BoxStream<'static, ReturnValue> = stream.boxed();
Ok(stream.to_output_stream())
}