nushell/crates/nu-cli/src/print.rs
Antoine Stevan 8403fff345
allow print to take data as input again (#9823)
related to
https://discord.com/channels/601130461678272522/601130461678272524/1134079115134251129

# Description
before 0.83.0, `print` used to allow piping data into it, e.g.
```nushell
"foo" | print
```
instead of 
```nushell
print "foo"
```

this PR enables the `any -> nothing` input / output type to allow this
again.

i've double checked and `print` is essentially the following snippet
```rust
        if !args.is_empty() {
            for arg in args {
                arg.into_pipeline_data()
                    .print(engine_state, stack, no_newline, to_stderr)?;
            }
        } else if !input.is_nothing() {
            input.print(engine_state, stack, no_newline, to_stderr)?;
        }
```
1. the first part is for `print a b c`
2. the second part is for `"foo" | print`

# User-Facing Changes
```nushell
"foo" | print
```
works again

# Tests + Formatting
- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
-  `toolkit test`
-  `toolkit test stdlib`

# After Submitting

---------

Co-authored-by: sholderbach <sholderbach@users.noreply.github.com>
2023-07-27 21:40:25 +02:00

88 lines
2.6 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, Type,
Value,
};
#[derive(Clone)]
pub struct Print;
impl Command for Print {
fn name(&self) -> &str {
"print"
}
fn signature(&self) -> Signature {
Signature::build("print")
.input_output_types(vec![
(Type::Nothing, Type::Nothing),
(Type::Any, Type::Nothing),
])
.allow_variants_without_examples(true)
.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");
// This will allow for easy printing of pipelines as well
if !args.is_empty() {
for arg in args {
arg.into_pipeline_data()
.print(engine_state, stack, no_newline, to_stderr)?;
}
} else if !input.is_nothing() {
input.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,
},
]
}
}