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Remove length collecting its input (#3292)

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* Remove length collecting its input

* Update length.rs
This commit is contained in:
Jonathan Turner 2021-04-10 10:21:51 +12:00 committed by GitHub
parent 80f5e14512
commit f5aa53c530
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1 changed files with 51 additions and 24 deletions
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71
crates/nu-command/src/commands/length.rs
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@ -2,7 +2,7 @@ use crate::prelude::*;
use nu_engine::WholeStreamCommand;
use nu_errors::ShellError;
use nu_protocol::{Signature, UntaggedValue, Value};
use nu_protocol::{ReturnSuccess, ReturnValue, Signature, UntaggedValue};
pub struct Length;
@ -31,30 +31,14 @@ impl WholeStreamCommand for Length {
fn run(&self, args: CommandArgs) -> Result<OutputStream, ShellError> {
let tag = args.call_info.name_tag.clone();
let (LengthArgs { column }, input) = args.process()?;
let rows: Vec<Value> = input.collect();
let length = if column {
if rows.is_empty() {
0
} else {
match &rows[0].value {
UntaggedValue::Row(dictionary) => dictionary.length(),
_ => {
return Err(ShellError::labeled_error(
"Cannot obtain column length",
"cannot obtain column length",
Ok(CountIterator {
column,
input,
done: false,
tag,
));
}
}
}
} else {
rows.len()
};
Ok(OutputStream::one(
UntaggedValue::int(length).into_value(tag),
))
.to_output_stream())
}
fn examples(&self) -> Vec<Example> {
@ -73,6 +57,49 @@ impl WholeStreamCommand for Length {
}
}
struct CountIterator {
column: bool,
input: InputStream,
done: bool,
tag: Tag,
}
impl Iterator for CountIterator {
type Item = ReturnValue;
fn next(&mut self) -> Option<Self::Item> {
if self.done {
return None;
}
self.done = true;
let length = if self.column {
if let Some(first) = self.input.next() {
match &first.value {
UntaggedValue::Row(dictionary) => dictionary.length(),
_ => {
return Some(Err(ShellError::labeled_error(
"Cannot obtain column length",
"cannot obtain column length",
self.tag.clone(),
)));
}
}
} else {
0
}
} else {
let input = &mut self.input;
input.count()
};
Some(Ok(ReturnSuccess::Value(
UntaggedValue::int(length).into_value(self.tag.clone()),
)))
}
}
#[cfg(test)]
mod tests {
use super::Length;