Use serde JSON to decompose a serialised flat object into a tuple of different structs

cascade_deser.rs

use serde::de::DeserializeOwned;

trait JsonDeserializable {
    fn deser<T: DeserializeOwned>(self) -> serde_json::Result<T>;
}

impl JsonDeserializable for serde_json::Value {
    fn deser<T: DeserializeOwned>(self) -> serde_json::Result<T> {
        serde_json::from_value(self)
    }
}

impl JsonDeserializable for &[u8] {
    fn deser<T: DeserializeOwned>(self) -> serde_json::Result<T> {
        serde_json::from_slice(self)
    }
}

impl JsonDeserializable for &str {
    fn deser<T: DeserializeOwned>(self) -> serde_json::Result<T> {
        serde_json::from_str(self)
    }
}

macro_rules! cascade_deser {
    ($value:expr, $($y:ident),+) => {{
        #[derive(serde::Deserialize)]
        struct Inner {
            $(
                #[serde(flatten)]
                $y: $y,
            )+
            #[serde(flatten)]
            _other: serde_json::Value,
        }
        
        JsonDeserializable::deser::<Inner>($value).map(|inner| {
            (
                $(
                    inner.$y,
                )+
                inner._other
            )
        })
    }};
}