nushell/crates/nu-cli/src/commands/trim.rs
Jason Gedge 522a828687
Move external closer to internal (#1611)
* Refactor InputStream and affected commands.

First, making `values` private and leaning on the `Stream` implementation makes
consumes of `InputStream` less likely to have to change in the future, if we
change what an `InputStream` is internally.

Second, we're dropping `Option<InputStream>` as the input to pipelines,
internals, and externals. Instead, `InputStream.is_empty` can be used to check
for "emptiness". Empty streams are typically only ever used as the first input
to a pipeline.

* Add run_external internal command.

We want to push external commands closer to internal commands, eventually
eliminating the concept of "external" completely. This means we can consolidate
a couple of things:

- Variable evaluation (for example, `$it`, `$nu`, alias vars)
- Behaviour of whole stream vs per-item external execution

It should also make it easier for us to start introducing argument signatures
for external commands,

* Update run_external.rs

* Update run_external.rs

* Update run_external.rs

* Update run_external.rs

Co-authored-by: Jonathan Turner <jonathandturner@users.noreply.github.com>
2020-04-20 15:30:44 +12:00

40 lines
934 B
Rust

use crate::commands::WholeStreamCommand;
use crate::prelude::*;
use nu_errors::ShellError;
use nu_protocol::{ReturnSuccess, Signature, UntaggedValue};
pub struct Trim;
impl WholeStreamCommand for Trim {
fn name(&self) -> &str {
"trim"
}
fn signature(&self) -> Signature {
Signature::build("trim")
}
fn usage(&self) -> &str {
"Trim leading and following whitespace from text data."
}
fn run(
&self,
args: CommandArgs,
registry: &CommandRegistry,
) -> Result<OutputStream, ShellError> {
trim(args, registry)
}
}
fn trim(args: CommandArgs, _registry: &CommandRegistry) -> Result<OutputStream, ShellError> {
Ok(args
.input
.map(move |v| {
let string = String::extract(&v)?;
ReturnSuccess::value(UntaggedValue::string(string.trim()).into_value(v.tag()))
})
.to_output_stream())
}