nu_command/debug/
view_span.rs

1use nu_engine::command_prelude::*;
2use nu_protocol::{DataSource, PipelineMetadata};
3
4#[derive(Clone)]
5pub struct ViewSpan;
6
7impl Command for ViewSpan {
8    fn name(&self) -> &str {
9        "view span"
10    }
11
12    fn description(&self) -> &str {
13        "View the contents of a span."
14    }
15
16    fn extra_description(&self) -> &str {
17        "This command is meant for debugging purposes.\nIt allows you to view the contents of nushell spans.\nOne way to get spans is to pipe something into 'debug --raw'.\nThen you can use the Span { start, end } values as the start and end values for this command."
18    }
19
20    fn signature(&self) -> nu_protocol::Signature {
21        Signature::build("view span")
22            .input_output_types(vec![(Type::Nothing, Type::String)])
23            .required("start", SyntaxShape::Int, "Start of the span.")
24            .required("end", SyntaxShape::Int, "End of the span.")
25            .category(Category::Debug)
26    }
27
28    fn run(
29        &self,
30        engine_state: &EngineState,
31        stack: &mut Stack,
32        call: &Call,
33        _input: PipelineData,
34    ) -> Result<PipelineData, ShellError> {
35        let start_span: Spanned<usize> = call.req(engine_state, stack, 0)?;
36        let end_span: Spanned<usize> = call.req(engine_state, stack, 1)?;
37
38        let source = if start_span.item < end_span.item {
39            let bin_contents =
40                engine_state.get_span_contents(Span::new(start_span.item, end_span.item));
41            Ok(
42                Value::string(String::from_utf8_lossy(bin_contents), call.head)
43                    .into_pipeline_data(),
44            )
45        } else {
46            Err(ShellError::GenericError {
47                error: "Cannot view span".to_string(),
48                msg: "this start and end does not correspond to a viewable value".to_string(),
49                span: Some(call.head),
50                help: None,
51                inner: vec![],
52            })
53        };
54
55        source.map(|x| {
56            x.set_metadata(Some(PipelineMetadata {
57                data_source: DataSource::None,
58                content_type: Some("application/x-nuscript".into()),
59            }))
60        })
61    }
62
63    fn examples(&self) -> Vec<Example> {
64        vec![Example {
65            description: "View the source of a span. 1 and 2 are just example values. Use the return of debug --raw to get the actual values",
66            example: r#"some | pipeline | or | variable | debug --raw; view span 1 2"#,
67            result: None,
68        }]
69    }
70}
nu_command/debug/view_span.rs

nu_command/debug/
view_span.rs
