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

use crate::commands::WholeStreamCommand;
use crate::prelude::*;
use nu_errors::ShellError;
use nu_protocol::{ReturnSuccess, Signature, UntaggedValue};

pub struct Debug;

#[derive(Deserialize)]
pub struct DebugArgs {
    raw: bool,
}

impl WholeStreamCommand for Debug {
    fn name(&self) -> &str {
        "debug"
    }

    fn signature(&self) -> Signature {
        Signature::build("debug").switch("raw", "Prints the raw value representation.", Some('r'))
    }

    fn usage(&self) -> &str {
        "Print the Rust debug representation of the values"
    }

    fn run(
        &self,
        args: CommandArgs,
        registry: &CommandRegistry,
    ) -> Result<OutputStream, ShellError> {
        debug_value(args, registry)
    }
}

fn debug_value(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputStream, ShellError> {
    let registry = registry.clone();
    let stream = async_stream! {
        let (DebugArgs { raw }, mut input) = args.process(&registry).await?;
        while let Some(v) = input.next().await {
            if raw {
                yield ReturnSuccess::value(
                    UntaggedValue::string(format!("{:#?}", v)).into_untagged_value(),
                );
            } else {
                yield ReturnSuccess::debug_value(v);
            }
        }
    };

    Ok(stream.to_output_stream())
}