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use quote::quote_spanned;
use super::{
OperatorCategory, OperatorConstraints, OperatorWriteOutput, WriteContextArgs,
RANGE_0, RANGE_1,
};
/// > 1 input stream, 1 output stream
///
/// For each item passed in, treat it as a [`Stream`](https://docs.rs/futures/latest/futures/stream/trait.Stream.html)
/// and emit its elements one by one. The type of the input items must implement `Stream`.
/// When the inner stream yields `Pending`, this operator yields `Pending` as well.
///
/// ```dfir
/// source_iter(vec![futures::stream::iter(vec![1, 2]), futures::stream::iter(vec![3])])
/// -> flatten_stream_blocking()
/// -> assert_eq([1, 2, 3]);
/// ```
pub const FLATTEN_STREAM_BLOCKING: OperatorConstraints = OperatorConstraints {
name: "flatten_stream_blocking",
categories: &[OperatorCategory::Flatten],
hard_range_inn: RANGE_1,
soft_range_inn: RANGE_1,
hard_range_out: RANGE_1,
soft_range_out: RANGE_1,
num_args: 0,
persistence_args: RANGE_0,
type_args: RANGE_0,
is_external_input: false,
has_singleton_output: false,
flo_type: None,
ports_inn: None,
ports_out: None,
input_delaytype_fn: |_| None,
write_fn: |&WriteContextArgs {
root,
op_span,
ident,
inputs,
outputs,
is_pull,
..
},
_| {
let write_iterator = if is_pull {
let input = &inputs[0];
quote_spanned! {op_span=>
let #ident = #root::dfir_pipes::pull::Pull::flatten_stream(#input);
}
} else {
let output = &outputs[0];
quote_spanned! {op_span=>
let #ident = #root::dfir_pipes::push::flatten_stream(#output);
}
};
Ok(OperatorWriteOutput {
write_iterator,
..Default::default()
})
},
};