1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
use quote::quote_spanned;
use super::{
OperatorCategory, OperatorConstraints, OperatorWriteOutput,
WriteContextArgs, RANGE_0, RANGE_1,
};
/// > Arguments: A single closure `FnMut(&Item)`.
///
/// An operator which allows you to "inspect" each element of a stream without
/// modifying it. The closure is called on a reference to each item. This is
/// mainly useful for debugging as in the example below, and it is generally an
/// anti-pattern to provide a closure with side effects.
///
/// > Note: The closure has access to the [`context` object](surface_flows.mdx#the-context-object).
///
/// ```hydroflow
/// source_iter([1, 2, 3, 4])
/// -> inspect(|x| println!("{}", x))
/// -> assert_eq([1, 2, 3, 4]);
/// ```
pub const INSPECT: OperatorConstraints = OperatorConstraints {
name: "inspect",
categories: &[OperatorCategory::Map],
hard_range_inn: RANGE_1,
soft_range_inn: RANGE_1,
hard_range_out: &(0..=1),
soft_range_out: &(0..=1),
num_args: 1,
persistence_args: RANGE_0,
type_args: RANGE_0,
is_external_input: false,
has_singleton_output: false,
ports_inn: None,
ports_out: None,
input_delaytype_fn: |_| None,
write_fn: |&WriteContextArgs {
root,
op_span,
ident,
inputs,
outputs,
is_pull,
arguments,
..
},
_| {
let write_iterator = if is_pull {
let input = &inputs[0];
quote_spanned! {op_span=>
let #ident = #input.inspect(#arguments);
}
} else if outputs.is_empty() {
quote_spanned! {op_span=>
let #ident = #root::pusherator::inspect::Inspect::new(#arguments, #root::pusherator::null::Null::new());
}
} else {
let output = &outputs[0];
quote_spanned! {op_span=>
let #ident = #root::pusherator::inspect::Inspect::new(#arguments, #output);
}
};
Ok(OperatorWriteOutput {
write_iterator,
..Default::default()
})
},
};