Negative indexing for range (#3427)

* adds negative indexing to range

* fixes tests to reflect new parsing changes

* removes duplicate definitons

* fmt
This commit is contained in:
Alex Shadley 2021-05-16 22:08:47 -05:00 committed by GitHub
parent dc9cd7d8b9
commit 86e6fcd309
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2 changed files with 79 additions and 6 deletions

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@ -1,7 +1,7 @@
use crate::prelude::*; use crate::prelude::*;
use nu_engine::WholeStreamCommand; use nu_engine::WholeStreamCommand;
use nu_errors::ShellError; use nu_errors::ShellError;
use nu_protocol::{Signature, SyntaxShape, Value}; use nu_protocol::{Signature, SyntaxShape, UntaggedValue, Value};
struct RangeArgs { struct RangeArgs {
range: nu_protocol::Range, range: nu_protocol::Range,
@ -26,6 +26,29 @@ impl WholeStreamCommand for Range {
"Return only the selected rows." "Return only the selected rows."
} }
fn examples(&self) -> Vec<Example> {
vec![
Example {
description: "Return rows 1 through 3",
example: "echo [1 2 3 4 5] | range 1..3",
result: Some(vec![
UntaggedValue::int(2).into(),
UntaggedValue::int(3).into(),
UntaggedValue::int(4).into(),
]),
},
Example {
description: "Return the third row from the end, through to the end",
example: "echo [1 2 3 4 5] | range (-3..)",
result: Some(vec![
UntaggedValue::int(3).into(),
UntaggedValue::int(4).into(),
UntaggedValue::int(5).into(),
]),
},
]
}
fn run(&self, args: CommandArgs) -> Result<OutputStream, ShellError> { fn run(&self, args: CommandArgs) -> Result<OutputStream, ShellError> {
range(args) range(args)
} }
@ -37,13 +60,40 @@ fn range(args: CommandArgs) -> Result<OutputStream, ShellError> {
range: args.req(0)?, range: args.req(0)?,
}; };
let from = cmd_args.range.min_usize()?; let from_raw = cmd_args.range.min_i64()?;
let to = cmd_args.range.max_usize()?; let to_raw = cmd_args.range.max_i64()?;
// only collect the input if we have any negative indices
if from_raw < 0 || to_raw < 0 {
let input = args.input.into_vec();
let input_size = input.len() as i64;
if from > to { let from = if from_raw < 0 {
Ok(OutputStream::one(Value::nothing())) (input_size + from_raw) as usize
} else {
from_raw as usize
};
let to = if to_raw < 0 {
(input_size + to_raw) as usize
} else if to_raw > input.len() as i64 {
input.len()
} else {
to_raw as usize
};
if from > to {
Ok(OutputStream::one(Value::nothing()))
} else {
Ok(OutputStream::from(input[from..to].to_vec()))
}
} else { } else {
Ok(args.input.skip(from).take(to - from + 1).to_output_stream()) let from = from_raw as usize;
let to = to_raw as usize;
if from > to {
Ok(OutputStream::one(Value::nothing()))
} else {
Ok(args.input.skip(from).take(to - from + 1).to_output_stream())
}
} }
} }

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@ -43,3 +43,26 @@ fn selects_some_rows() {
assert_eq!(actual.out, "2"); assert_eq!(actual.out, "2");
}); });
} }
#[test]
fn negative_indices() {
Playground::setup("range_test_negative_indices", |dirs, sandbox| {
sandbox.with_files(vec![
EmptyFile("notes.txt"),
EmptyFile("tests.txt"),
EmptyFile("persons.txt"),
]);
let actual = nu!(
cwd: dirs.test(), pipeline(
r#"
ls
| get name
| range (-1..)
| length
"#
));
assert_eq!(actual.out, "1");
});
}