dfir_lang/graph/ops/
identity.rs

1use super::{
2    OperatorCategory, OperatorConstraints, IDENTITY_WRITE_FN, RANGE_0, RANGE_1,
3};
4
5/// > 1 input stream of type T, 1 output stream of type T
6///
7/// For each item passed in, pass it out without any change.
8///
9/// ```dfir
10/// source_iter(vec!["hello", "world"])
11///     -> identity()
12///     -> assert_eq(["hello", "world"]);
13/// ```
14///
15/// You can also supply a type parameter `identity::<MyType>()` to specify what items flow through the
16/// the pipeline. This can be useful for helping the compiler infer types.
17///
18/// ```dfir
19/// // Use type parameter to ensure items are `i32`s.
20/// source_iter(0..10)
21///     -> identity::<i32>()
22///     -> assert_eq([0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
23/// ```
24pub const IDENTITY: OperatorConstraints = OperatorConstraints {
25    name: "identity",
26    categories: &[OperatorCategory::Map],
27    hard_range_inn: RANGE_1,
28    soft_range_inn: RANGE_1,
29    hard_range_out: RANGE_1,
30    soft_range_out: RANGE_1,
31    num_args: 0,
32    persistence_args: RANGE_0,
33    type_args: &(0..=1),
34    is_external_input: false,
35    has_singleton_output: false,
36    flo_type: None,
37    ports_inn: None,
38    ports_out: None,
39    input_delaytype_fn: |_| None,
40    write_fn: IDENTITY_WRITE_FN,
41};