dfir_lang/graph/ops/
source_stdin.rs

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1use quote::quote_spanned;
2
3use super::{
4    FloType, OperatorCategory, OperatorConstraints, OperatorWriteOutput, WriteContextArgs, RANGE_0,
5    RANGE_1,
6};
7
8/// > 0 input streams, 1 output stream
9///
10/// > Arguments: port number
11///
12/// `source_stdin` receives a Stream of lines from stdin
13/// and emits each of the elements it receives downstream.
14///
15/// ```dfir
16/// source_stdin()
17///     -> map(|x| x.unwrap().to_uppercase())
18///     -> for_each(|x| println!("{}", x));
19/// ```
20pub const SOURCE_STDIN: OperatorConstraints = OperatorConstraints {
21    name: "source_stdin",
22    categories: &[OperatorCategory::Source],
23    hard_range_inn: RANGE_0,
24    soft_range_inn: RANGE_0,
25    hard_range_out: RANGE_1,
26    soft_range_out: RANGE_1,
27    num_args: 0,
28    persistence_args: RANGE_0,
29    type_args: RANGE_0,
30    is_external_input: true,
31    has_singleton_output: false,
32    flo_type: Some(FloType::Source),
33    ports_inn: None,
34    ports_out: None,
35    input_delaytype_fn: |_| None,
36    write_fn: |wc @ &WriteContextArgs {
37                   root,
38                   context,
39                   op_span,
40                   ident,
41                   ..
42               },
43               _| {
44        let stream_ident = wc.make_ident("stream");
45        let write_prologue = quote_spanned! {op_span=>
46            #[expect(clippy::let_and_return, reason = "gives return value a self-documenting name")]
47            let mut #stream_ident = {
48                use #root::tokio::io::AsyncBufReadExt;
49                let reader = #root::tokio::io::BufReader::new(#root::tokio::io::stdin());
50                let stdin_lines = #root::tokio_stream::wrappers::LinesStream::new(reader.lines());
51                stdin_lines
52            };
53        };
54        let write_iterator = quote_spanned! {op_span=>
55            let #ident = std::iter::from_fn(|| {
56                match #root::futures::stream::Stream::poll_next(std::pin::Pin::new(&mut #stream_ident), &mut std::task::Context::from_waker(&#context.waker())) {
57                    std::task::Poll::Ready(maybe) => maybe,
58                    std::task::Poll::Pending => None,
59                }
60            });
61        };
62        Ok(OperatorWriteOutput {
63            write_prologue,
64            write_iterator,
65            ..Default::default()
66        })
67    },
68};
dfir_lang/graph/ops/source_stdin.rs

dfir_lang/graph/ops/
source_stdin.rs
