forked from extern/nushell
69 lines
1.7 KiB
Rust
69 lines
1.7 KiB
Rust
use crate::prelude::*;
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use nu_engine::WholeStreamCommand;
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use nu_errors::ShellError;
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use nu_protocol::{Signature, SyntaxShape, UntaggedValue, Value};
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#[derive(Deserialize)]
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struct PrependArgs {
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row: Value,
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}
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pub struct Prepend;
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#[async_trait]
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impl WholeStreamCommand for Prepend {
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fn name(&self) -> &str {
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"prepend"
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}
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fn signature(&self) -> Signature {
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Signature::build("prepend").required(
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"row value",
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SyntaxShape::Any,
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"the value of the row to prepend to the table",
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)
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}
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fn usage(&self) -> &str {
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"Prepend the given row to the front of the table"
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}
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async fn run(&self, args: CommandArgs) -> Result<OutputStream, ShellError> {
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prepend(args).await
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}
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fn examples(&self) -> Vec<Example> {
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vec![Example {
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description: "Add something to the beginning of a list or table",
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example: "echo [2 3 4] | prepend 1",
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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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UntaggedValue::int(3).into(),
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UntaggedValue::int(4).into(),
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]),
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}]
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}
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}
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async fn prepend(args: CommandArgs) -> Result<OutputStream, ShellError> {
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let (PrependArgs { row }, input) = args.process().await?;
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let bos = futures::stream::iter(vec![row]);
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Ok(bos.chain(input).to_output_stream())
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}
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#[cfg(test)]
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mod tests {
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use super::Prepend;
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use super::ShellError;
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#[test]
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fn examples_work_as_expected() -> Result<(), ShellError> {
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use crate::examples::test as test_examples;
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test_examples(Prepend {})
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}
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}
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