forked from extern/nushell
88 lines
2.2 KiB
Rust
88 lines
2.2 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, UntaggedValue, Value};
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pub struct Length;
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#[derive(Deserialize)]
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pub struct LengthArgs {
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column: bool,
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}
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impl WholeStreamCommand for Length {
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fn name(&self) -> &str {
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"length"
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}
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fn signature(&self) -> Signature {
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Signature::build("length").switch(
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"column",
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"Calculate number of columns in table",
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Some('c'),
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)
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}
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fn usage(&self) -> &str {
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"Show the total number of rows or items."
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}
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fn run(&self, args: CommandArgs) -> Result<OutputStream, ShellError> {
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let tag = args.call_info.name_tag.clone();
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let (LengthArgs { column }, input) = args.process()?;
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let rows: Vec<Value> = input.collect();
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let length = if column {
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if rows.is_empty() {
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0
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} else {
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match &rows[0].value {
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UntaggedValue::Row(dictionary) => dictionary.length(),
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_ => {
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return Err(ShellError::labeled_error(
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"Cannot obtain column length",
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"cannot obtain column length",
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tag,
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));
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}
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}
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}
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} else {
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rows.len()
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};
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Ok(OutputStream::one(
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UntaggedValue::int(length).into_value(tag),
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))
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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: "Count the number of entries in a list",
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example: "echo [1 2 3 4 5] | length",
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result: Some(vec![UntaggedValue::int(5).into()]),
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},
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Example {
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description: "Count the number of columns in the calendar table",
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example: "cal | length -c",
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result: None,
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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::Length;
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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(Length {})
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}
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}
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