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

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use crate::commands::classified::block::run_block;
use crate::commands::WholeStreamCommand;
use crate::context::CommandRegistry;
use crate::data::value::merge_values;
use crate::prelude::*;
use indexmap::IndexMap;
use nu_errors::ShellError;
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use nu_protocol::{hir::Block, ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
pub struct Merge;
#[derive(Deserialize)]
pub struct MergeArgs {
block: Block,
}
impl WholeStreamCommand for Merge {
fn name(&self) -> &str {
"merge"
}
fn signature(&self) -> Signature {
Signature::build("merge").required(
"block",
SyntaxShape::Block,
"the block to run and merge into the table",
)
}
fn usage(&self) -> &str {
"Merge a table."
}
fn run(
&self,
args: CommandArgs,
registry: &CommandRegistry,
) -> Result<OutputStream, ShellError> {
merge(args, registry)
}
fn examples(&self) -> Vec<Example> {
vec![Example {
description: "Merge a 1-based index column with some ls output",
example: "ls | select name | keep 3 | merge { echo [1 2 3] | wrap index }",
result: None,
}]
}
}
fn merge(raw_args: CommandArgs, registry: &CommandRegistry) -> Result<OutputStream, ShellError> {
let registry = registry.clone();
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let scope = raw_args.call_info.scope.clone();
let stream = async_stream! {
let mut context = Context::from_raw(&raw_args, &registry);
let name_tag = raw_args.call_info.name_tag.clone();
let (merge_args, mut input): (MergeArgs, _) = raw_args.process(&registry).await?;
let block = merge_args.block;
let table: Option<Vec<Value>> = match run_block(&block,
&mut context,
InputStream::empty(),
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&scope.it,
&scope.vars,
&scope.env).await {
Ok(mut stream) => Some(stream.drain_vec().await),
Err(err) => {
yield Err(err);
return;
}
};
let table = table.unwrap_or_else(|| vec![Value {
value: UntaggedValue::row(IndexMap::default()),
tag: name_tag,
}]);
let mut idx = 0;
while let Some(value) = input.next().await {
let other = table.get(idx);
match other {
Some(replacement) => {
match merge_values(&value.value, &replacement.value) {
Ok(merged_value) => yield ReturnSuccess::value(merged_value.into_value(&value.tag)),
Err(err) => {
let message = format!("The row at {:?} types mismatch", idx);
yield Err(ShellError::labeled_error("Could not merge", &message, &value.tag));
}
}
}
None => yield ReturnSuccess::value(value),
}
idx += 1;
}
};
Ok(stream.to_output_stream())
}
#[cfg(test)]
mod tests {
use super::Merge;
#[test]
fn examples_work_as_expected() {
use crate::examples::test as test_examples;
test_examples(Merge {})
}
}