dfir_lang/graph/ops/
tee.rs

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1use quote::{quote_spanned, ToTokens};
2
3use super::{
4    OperatorCategory, OperatorConstraints, OperatorWriteOutput, WriteContextArgs, RANGE_0, RANGE_1,
5    RANGE_ANY,
6};
7
8/// > 1 input stream, *n* output streams
9///
10/// Takes the input stream and delivers a copy of each item to each output.
11/// > Note: Downstream operators may need explicit type annotations.
12///
13/// ```dfir
14/// my_tee = source_iter(vec!["Hello", "World"]) -> tee();
15/// my_tee -> map(|x: &str| x.to_uppercase()) -> assert_eq(["HELLO", "WORLD"]);
16/// my_tee -> map(|x: &str| x.to_lowercase()) -> assert_eq(["hello", "world"]);
17/// my_tee -> assert_eq(["Hello", "World"]);
18/// ```
19pub const TEE: OperatorConstraints = OperatorConstraints {
20    name: "tee",
21    categories: &[OperatorCategory::MultiOut],
22    hard_range_inn: RANGE_1,
23    soft_range_inn: RANGE_1,
24    hard_range_out: RANGE_ANY,
25    soft_range_out: &(2..),
26    num_args: 0,
27    persistence_args: RANGE_0,
28    type_args: RANGE_0,
29    is_external_input: false,
30    has_singleton_output: false,
31    flo_type: None,
32    ports_inn: None,
33    ports_out: None,
34    input_delaytype_fn: |_| None,
35    write_fn: |&WriteContextArgs {
36                   root,
37                   op_span,
38                   op_name,
39                   ident,
40                   inputs,
41                   outputs,
42                   is_pull,
43                   ..
44               },
45               _| {
46        let write_iterator = if !is_pull {
47            let tees = outputs
48                .iter()
49                .rev()
50                .map(|i| i.to_token_stream())
51                .reduce(|b, a| quote_spanned! {op_span=> #root::pusherator::tee::Tee::new(#a, #b) })
52                .unwrap_or_else(
53                    || quote_spanned! {op_span=> #root::pusherator::for_each::ForEach::new(std::mem::drop) },
54                );
55            quote_spanned! {op_span=>
56                let #ident = #tees;
57            }
58        } else {
59            // Pull.
60            assert_eq!(1, inputs.len());
61            assert_eq!(
62                1,
63                outputs.len(),
64                "`{}()` marked as pull should have exactly one output, actually has {}. This is a bug.",
65                op_name,
66                outputs.len()
67            );
68            let input = &inputs[0];
69            quote_spanned! {op_span=>
70                let #ident = #input;
71            }
72        };
73        Ok(OperatorWriteOutput {
74            write_iterator,
75            ..Default::default()
76        })
77    },
78};
dfir_lang/graph/ops/tee.rs

dfir_lang/graph/ops/
tee.rs
