e4226def16
This commit extracts five new crates:
- nu-source, which contains the core source-code handling logic in Nu,
including Text, Span, and also the pretty.rs-based debug logic
- nu-parser, which is the parser and expander logic
- nu-protocol, which is the bulk of the types and basic conveniences
used by plugins
- nu-errors, which contains ShellError, ParseError and error handling
conveniences
- nu-textview, which is the textview plugin extracted into a crate
One of the major consequences of this refactor is that it's no longer
possible to `impl X for Spanned<Y>` outside of the `nu-source` crate, so
a lot of types became more concrete (Value became a concrete type
instead of Spanned<Value>, for example).
This also turned a number of inherent methods in the main nu crate into
plain functions (impl Value {} became a bunch of functions in the
`value` namespace in `crate::data::value`).
62 lines
1.5 KiB
Rust
62 lines
1.5 KiB
Rust
use crate::commands::WholeStreamCommand;
|
|
use crate::context::CommandRegistry;
|
|
use crate::prelude::*;
|
|
use nu_errors::ShellError;
|
|
use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, Value};
|
|
use nu_source::Tagged;
|
|
|
|
pub struct Last;
|
|
|
|
#[derive(Deserialize)]
|
|
pub struct LastArgs {
|
|
rows: Option<Tagged<u64>>,
|
|
}
|
|
|
|
impl WholeStreamCommand for Last {
|
|
fn name(&self) -> &str {
|
|
"last"
|
|
}
|
|
|
|
fn signature(&self) -> Signature {
|
|
Signature::build("last").optional(
|
|
"rows",
|
|
SyntaxShape::Number,
|
|
"starting from the back, the number of rows to return",
|
|
)
|
|
}
|
|
|
|
fn usage(&self) -> &str {
|
|
"Show only the last number of rows."
|
|
}
|
|
|
|
fn run(
|
|
&self,
|
|
args: CommandArgs,
|
|
registry: &CommandRegistry,
|
|
) -> Result<OutputStream, ShellError> {
|
|
args.process(registry, last)?.run()
|
|
}
|
|
}
|
|
|
|
fn last(LastArgs { rows }: LastArgs, context: RunnableContext) -> Result<OutputStream, ShellError> {
|
|
let stream = async_stream! {
|
|
let v: Vec<_> = context.input.into_vec().await;
|
|
|
|
let rows_desired = if let Some(quantity) = rows {
|
|
*quantity
|
|
} else {
|
|
1
|
|
};
|
|
|
|
let count = (rows_desired as usize);
|
|
if count < v.len() {
|
|
let k = v.len() - count;
|
|
for x in v[k..].iter() {
|
|
let y: Value = x.clone();
|
|
yield ReturnSuccess::value(y)
|
|
}
|
|
}
|
|
};
|
|
Ok(stream.to_output_stream())
|
|
}
|