mirror of
https://github.com/nushell/nushell.git
synced 2025-01-18 04:10:18 +01:00
eaec480f42
# Description This fix changes pipelines to allow them to actually be empty. Mapping over empty pipelines gives empty pipelines. Empty pipelines immediately return `None` when iterated. This removes a some of where `Span::new(0, 0)` was coming from, though there are other cases where we still use it. # 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.
77 lines
2.2 KiB
Rust
77 lines
2.2 KiB
Rust
use nu_engine::CallExt;
|
|
use nu_protocol::ast::Call;
|
|
use nu_protocol::engine::{Command, EngineState, Stack};
|
|
use nu_protocol::{
|
|
Category, Example, IntoPipelineData, PipelineData, ShellError, Signature, SyntaxShape, Value,
|
|
};
|
|
|
|
#[derive(Clone)]
|
|
pub struct Print;
|
|
|
|
impl Command for Print {
|
|
fn name(&self) -> &str {
|
|
"print"
|
|
}
|
|
|
|
fn signature(&self) -> Signature {
|
|
Signature::build("print")
|
|
.rest("rest", SyntaxShape::Any, "the values to print")
|
|
.switch(
|
|
"no-newline",
|
|
"print without inserting a newline for the line ending",
|
|
Some('n'),
|
|
)
|
|
.switch("stderr", "print to stderr instead of stdout", Some('e'))
|
|
.category(Category::Strings)
|
|
}
|
|
|
|
fn usage(&self) -> &str {
|
|
"Print the given values to stdout"
|
|
}
|
|
|
|
fn extra_usage(&self) -> &str {
|
|
r#"Unlike `echo`, this command does not return any value (`print | describe` will return "nothing").
|
|
Since this command has no output, there is no point in piping it with other commands.
|
|
|
|
`print` may be used inside blocks of code (e.g.: hooks) to display text during execution without interfering with the pipeline."#
|
|
}
|
|
|
|
fn search_terms(&self) -> Vec<&str> {
|
|
vec!["display"]
|
|
}
|
|
|
|
fn run(
|
|
&self,
|
|
engine_state: &EngineState,
|
|
stack: &mut Stack,
|
|
call: &Call,
|
|
_input: PipelineData,
|
|
) -> Result<PipelineData, ShellError> {
|
|
let args: Vec<Value> = call.rest(engine_state, stack, 0)?;
|
|
let no_newline = call.has_flag("no-newline");
|
|
let to_stderr = call.has_flag("stderr");
|
|
|
|
for arg in args {
|
|
arg.into_pipeline_data()
|
|
.print(engine_state, stack, no_newline, to_stderr)?;
|
|
}
|
|
|
|
Ok(PipelineData::empty())
|
|
}
|
|
|
|
fn examples(&self) -> Vec<Example> {
|
|
vec![
|
|
Example {
|
|
description: "Print 'hello world'",
|
|
example: r#"print "hello world""#,
|
|
result: None,
|
|
},
|
|
Example {
|
|
description: "Print the sum of 2 and 3",
|
|
example: r#"print (2 + 3)"#,
|
|
result: None,
|
|
},
|
|
]
|
|
}
|
|
}
|