forked from extern/nushell
149 lines
4.3 KiB
Rust
149 lines
4.3 KiB
Rust
use crate::commands::WholeStreamCommand;
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use crate::prelude::*;
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use nu_errors::ShellError;
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use nu_protocol::hir::Operator;
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use nu_protocol::{
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Primitive, Range, RangeInclusion, ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value,
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};
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pub struct Echo;
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#[derive(Deserialize)]
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pub struct EchoArgs {
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pub rest: Vec<Value>,
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}
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#[async_trait]
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impl WholeStreamCommand for Echo {
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fn name(&self) -> &str {
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"echo"
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}
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fn signature(&self) -> Signature {
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Signature::build("echo").rest(SyntaxShape::Any, "the values to echo")
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}
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fn usage(&self) -> &str {
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"Echo the arguments back to the user."
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}
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async fn run(
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&self,
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args: CommandArgs,
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registry: &CommandRegistry,
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) -> Result<OutputStream, ShellError> {
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echo(args, registry).await
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}
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fn examples(&self) -> Vec<Example> {
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vec![
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Example {
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description: "Put a hello message in the pipeline",
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example: "echo 'hello'",
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result: Some(vec![Value::from("hello")]),
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},
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Example {
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description: "Print the value of the special '$nu' variable",
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example: "echo $nu",
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result: None,
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},
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]
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}
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}
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async fn echo(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputStream, ShellError> {
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let registry = registry.clone();
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let (args, _): (EchoArgs, _) = args.process(®istry).await?;
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let stream = args.rest.into_iter().map(|i| match i.as_string() {
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Ok(s) => OutputStream::one(Ok(ReturnSuccess::Value(
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UntaggedValue::string(s).into_value(i.tag.clone()),
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))),
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_ => match i {
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Value {
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value: UntaggedValue::Table(table),
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..
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} => futures::stream::iter(table.into_iter().map(ReturnSuccess::value))
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.to_output_stream(),
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Value {
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value: UntaggedValue::Primitive(Primitive::Range(range)),
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tag,
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} => futures::stream::iter(RangeIterator::new(*range, tag)).to_output_stream(),
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_ => OutputStream::one(Ok(ReturnSuccess::Value(i.clone()))),
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},
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});
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Ok(futures::stream::iter(stream).flatten().to_output_stream())
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}
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struct RangeIterator {
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curr: Primitive,
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end: Primitive,
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tag: Tag,
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is_end_inclusive: bool,
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is_done: bool,
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}
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impl RangeIterator {
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pub fn new(range: Range, tag: Tag) -> RangeIterator {
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RangeIterator {
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curr: range.from.0.item,
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end: range.to.0.item,
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tag,
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is_end_inclusive: matches!(range.to.1, RangeInclusion::Inclusive),
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is_done: false,
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}
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}
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}
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impl Iterator for RangeIterator {
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type Item = Result<ReturnSuccess, ShellError>;
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fn next(&mut self) -> Option<Self::Item> {
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if self.curr != self.end {
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let output = UntaggedValue::Primitive(self.curr.clone()).into_value(self.tag.clone());
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self.curr = match crate::data::value::compute_values(
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Operator::Plus,
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&UntaggedValue::Primitive(self.curr.clone()),
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&UntaggedValue::int(1),
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) {
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Ok(result) => match result {
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UntaggedValue::Primitive(p) => p,
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_ => {
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return Some(Err(ShellError::unimplemented(
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"Internal error: expected a primitive result from increment",
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)));
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}
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},
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Err((left_type, right_type)) => {
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return Some(Err(ShellError::coerce_error(
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left_type.spanned(self.tag.span),
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right_type.spanned(self.tag.span),
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)));
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}
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};
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Some(ReturnSuccess::value(output))
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} else if self.is_end_inclusive && !self.is_done {
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self.is_done = true;
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Some(ReturnSuccess::value(
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UntaggedValue::Primitive(self.curr.clone()).into_value(self.tag.clone()),
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))
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} else {
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// TODO: add inclusive/exclusive ranges
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None
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}
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}
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}
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#[cfg(test)]
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mod tests {
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use super::Echo;
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#[test]
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fn examples_work_as_expected() {
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use crate::examples::test as test_examples;
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test_examples(Echo {})
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}
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}
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