forked from extern/nushell
84 lines
2.0 KiB
Rust
84 lines
2.0 KiB
Rust
use crate::commands::WholeStreamCommand;
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use crate::context::CommandRegistry;
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use crate::prelude::*;
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use nu_errors::ShellError;
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use nu_protocol::{Signature, SyntaxShape, UntaggedValue};
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use nu_source::Tagged;
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pub struct Drop;
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#[derive(Deserialize)]
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pub struct DropArgs {
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rows: Option<Tagged<u64>>,
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}
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#[async_trait]
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impl WholeStreamCommand for Drop {
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fn name(&self) -> &str {
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"drop"
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}
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fn signature(&self) -> Signature {
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Signature::build("drop").optional(
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"rows",
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SyntaxShape::Number,
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"starting from the back, the number of rows to drop",
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)
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}
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fn usage(&self) -> &str {
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"Drop the last number of rows."
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}
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async fn run(
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&self,
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args: CommandArgs,
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registry: &CommandRegistry,
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) -> Result<OutputStream, ShellError> {
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let (DropArgs { rows }, input) = args.process(®istry).await?;
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let mut v: Vec<_> = input.into_vec().await;
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let rows_to_drop = if let Some(quantity) = rows {
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*quantity as usize
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} else {
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1
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};
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for _ in 0..rows_to_drop {
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v.pop();
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}
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Ok(futures::stream::iter(v).to_output_stream())
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}
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fn examples(&self) -> Vec<Example> {
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vec![
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Example {
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description: "Remove the last item of a list/table",
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example: "echo [1 2 3] | drop",
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result: Some(vec![
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UntaggedValue::int(1).into(),
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UntaggedValue::int(2).into(),
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]),
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},
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Example {
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description: "Remove the last 2 items of a list/table",
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example: "echo [1 2 3] | drop 2",
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result: Some(vec![UntaggedValue::int(1).into()]),
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},
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]
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}
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}
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#[cfg(test)]
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mod tests {
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use super::Drop;
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#[test]
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fn examples_work_as_expected() {
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use crate::examples::test as test_examples;
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test_examples(Drop {})
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}
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}
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