forked from extern/nushell
a5c604c283
# Description Working on uniformizing the ending messages regarding methods usage() and extra_usage(). This is related to the issue https://github.com/nushell/nushell/issues/5066 after discussing it with @jntrnr # User-Facing Changes None. # Tests + Formatting Don't forget to add tests that cover your changes. Make sure you've run and fixed any issues with these commands: - `cargo fmt --all -- --check` to check standard code formatting (`cargo fmt --all` applies these changes) - `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A clippy::needless_collect` to check that you're using the standard code style - `cargo test --workspace` to check that all tests pass # After Submitting If your PR had any user-facing changes, update [the documentation](https://github.com/nushell/nushell.github.io) after the PR is merged, if necessary. This will help us keep the docs up to date.
96 lines
2.7 KiB
Rust
96 lines
2.7 KiB
Rust
use super::super::values::NuLazyFrame;
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use crate::dataframe::values::{Column, NuDataFrame};
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use nu_engine::CallExt;
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use nu_protocol::{
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ast::Call,
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engine::{Command, EngineState, Stack},
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Category, Example, PipelineData, ShellError, Signature, Span, SyntaxShape, Type, Value,
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};
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#[derive(Clone)]
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pub struct LazyFetch;
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impl Command for LazyFetch {
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fn name(&self) -> &str {
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"dfr fetch"
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}
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fn usage(&self) -> &str {
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"collects the lazyframe to the selected rows."
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}
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fn signature(&self) -> Signature {
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Signature::build(self.name())
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.required(
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"rows",
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SyntaxShape::Int,
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"number of rows to be fetched from lazyframe",
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)
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.input_type(Type::Custom("dataframe".into()))
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.output_type(Type::Custom("dataframe".into()))
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.category(Category::Custom("lazyframe".into()))
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}
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fn examples(&self) -> Vec<Example> {
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vec![Example {
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description: "Fetch a rows from the dataframe",
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example: "[[a b]; [6 2] [4 2] [2 2]] | dfr into-df | dfr fetch 2",
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result: Some(
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NuDataFrame::try_from_columns(vec![
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Column::new(
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"a".to_string(),
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vec![Value::test_int(6), Value::test_int(4)],
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),
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Column::new(
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"b".to_string(),
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vec![Value::test_int(2), Value::test_int(2)],
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),
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])
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.expect("simple df for test should not fail")
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.into_value(Span::test_data()),
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),
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}]
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}
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fn run(
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&self,
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engine_state: &EngineState,
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stack: &mut Stack,
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call: &Call,
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input: PipelineData,
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) -> Result<PipelineData, ShellError> {
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let rows: i64 = call.req(engine_state, stack, 0)?;
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let lazy = NuLazyFrame::try_from_pipeline(input, call.head)?;
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let eager: NuDataFrame = lazy
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.into_polars()
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.fetch(rows as usize)
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.map_err(|e| {
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ShellError::GenericError(
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"Error fetching rows".into(),
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e.to_string(),
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Some(call.head),
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None,
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Vec::new(),
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)
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})?
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.into();
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Ok(PipelineData::Value(
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NuDataFrame::into_value(eager, call.head),
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None,
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))
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}
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}
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#[cfg(test)]
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mod test {
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use super::super::super::test_dataframe::test_dataframe;
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use super::*;
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#[test]
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fn test_examples() {
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test_dataframe(vec![Box::new(LazyFetch {})])
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}
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}
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