cgp-dispatch 0.7.0

Extensible data type dispatchers for CGP handlers
Documentation 
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

use cgp_core::prelude::*;
use cgp_handler::{AsyncComputer, AsyncComputerComponent, Computer, ComputerComponent};

pub struct ExtractFieldAndHandle<Tag, Provider = UseContext>(pub PhantomData<(Tag, Provider)>);

#[cgp_provider]
impl<Context, Code, Input, Tag, Value, Provider, Output, Remainder> Computer<Context, Code, Input>
    for ExtractFieldAndHandle<Tag, Provider>
where
    Input: ExtractField<Tag, Value = Value, Remainder = Remainder>,
    Provider: Computer<Context, Code, Field<Tag, Value>, Output = Output>,
{
    type Output = Result<Output, Remainder>;

    fn compute(
        context: &Context,
        tag: PhantomData<Code>,
        input: Input,
    ) -> Result<Output, Remainder> {
        let value = input.extract_field(PhantomData::<Tag>)?;
        let output = Provider::compute(context, tag, value.into());
        Ok(output)
    }
}

#[cgp_provider]
impl<Context, Code, Input, Tag, Value, Provider, Output, Remainder>
    AsyncComputer<Context, Code, Input> for ExtractFieldAndHandle<Tag, Provider>
where
    Input: ExtractField<Tag, Value = Value, Remainder = Remainder>,
    Provider: AsyncComputer<Context, Code, Field<Tag, Value>, Output = Output>,
{
    type Output = Result<Output, Remainder>;

    async fn compute_async(
        context: &Context,
        tag: PhantomData<Code>,
        input: Input,
    ) -> Result<Output, Remainder> {
        let value = input.extract_field(PhantomData::<Tag>);

        match value {
            Ok(value) => {
                let output = Provider::compute_async(context, tag, value.into()).await;
                Ok(output)
            }
            Err(remainder) => Err(remainder),
        }
    }
}