nushell/crates/nu-cli/src/commands/default.rs

92 lines
2.4 KiB
Rust

use crate::commands::WholeStreamCommand;
use crate::context::CommandRegistry;
use crate::prelude::*;
use nu_errors::ShellError;
use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
use nu_source::Tagged;
use nu_value_ext::ValueExt;
#[derive(Deserialize)]
struct DefaultArgs {
column: Tagged<String>,
value: Value,
}
pub struct Default;
impl WholeStreamCommand for Default {
fn name(&self) -> &str {
"default"
}
fn signature(&self) -> Signature {
Signature::build("default")
.required("column name", SyntaxShape::String, "the name of the column")
.required(
"column value",
SyntaxShape::Any,
"the value of the column to default",
)
}
fn usage(&self) -> &str {
"Sets a default row's column if missing."
}
fn run(
&self,
args: CommandArgs,
registry: &CommandRegistry,
) -> Result<OutputStream, ShellError> {
default(args, registry)
}
fn examples(&self) -> Vec<Example> {
vec![Example {
description: "Give a default 'target' to all file entries",
example: "ls -af | default target 'nothing'",
result: None,
}]
}
}
fn default(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputStream, ShellError> {
let registry = registry.clone();
let stream = async_stream! {
let (DefaultArgs { column, value }, mut input) = args.process(&registry).await?;
while let Some(item) = input.next().await {
let should_add = match item {
Value {
value: UntaggedValue::Row(ref r),
..
} => r.get_data(&column.item).borrow().is_none(),
_ => false,
};
if should_add {
match item.insert_data_at_path(&column.item, value.clone()) {
Some(new_value) => yield ReturnSuccess::value(new_value),
None => yield ReturnSuccess::value(item),
}
} else {
yield ReturnSuccess::value(item);
}
}
};
Ok(stream.to_output_stream())
}
#[cfg(test)]
mod tests {
use super::Default;
#[test]
fn examples_work_as_expected() {
use crate::examples::test as test_examples;
test_examples(Default {})
}
}