86e6fcd309
* adds negative indexing to range * fixes tests to reflect new parsing changes * removes duplicate definitons * fmt
112 lines
2.9 KiB
Rust
112 lines
2.9 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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struct RangeArgs {
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range: nu_protocol::Range,
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}
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pub struct Range;
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impl WholeStreamCommand for Range {
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fn name(&self) -> &str {
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"range"
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}
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fn signature(&self) -> Signature {
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Signature::build("range").required(
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"rows",
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SyntaxShape::Range,
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"range of rows to return: Eg) 4..7 (=> from 4 to 7)",
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)
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}
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fn usage(&self) -> &str {
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"Return only the selected rows."
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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: "Return rows 1 through 3",
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example: "echo [1 2 3 4 5] | range 1..3",
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result: Some(vec![
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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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Example {
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description: "Return the third row from the end, through to the end",
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example: "echo [1 2 3 4 5] | range (-3..)",
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result: Some(vec![
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UntaggedValue::int(3).into(),
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UntaggedValue::int(4).into(),
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UntaggedValue::int(5).into(),
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]),
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},
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]
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}
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fn run(&self, args: CommandArgs) -> Result<OutputStream, ShellError> {
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range(args)
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}
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}
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fn range(args: CommandArgs) -> Result<OutputStream, ShellError> {
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let args = args.evaluate_once()?;
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let cmd_args = RangeArgs {
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range: args.req(0)?,
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};
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let from_raw = cmd_args.range.min_i64()?;
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let to_raw = cmd_args.range.max_i64()?;
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// only collect the input if we have any negative indices
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if from_raw < 0 || to_raw < 0 {
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let input = args.input.into_vec();
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let input_size = input.len() as i64;
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let from = if from_raw < 0 {
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(input_size + from_raw) as usize
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} else {
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from_raw as usize
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};
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let to = if to_raw < 0 {
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(input_size + to_raw) as usize
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} else if to_raw > input.len() as i64 {
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input.len()
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} else {
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to_raw as usize
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};
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if from > to {
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Ok(OutputStream::one(Value::nothing()))
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} else {
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Ok(OutputStream::from(input[from..to].to_vec()))
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}
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} else {
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let from = from_raw as usize;
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let to = to_raw as usize;
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if from > to {
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Ok(OutputStream::one(Value::nothing()))
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} else {
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Ok(args.input.skip(from).take(to - from + 1).to_output_stream())
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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::Range;
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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(Range {})
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}
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}
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