clone-fields

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按字段类型克隆。不多也不少。

use clone_fields::{CloneFields, CloneInto, CloneFrom};

// PartialEq and Debug traits are only required for `assert` macros in the example.
#[derive(PartialEq, Debug, CloneFields)]
#[destinations("External")]
struct Original<'a, T: Clone> {
    field1: &'a i64,
    field2: T,
    nested: OriginalNested,
}

#[derive(PartialEq, Debug, CloneFields)]
#[destinations("ExternalNested", "ExternalNested2")]
struct OriginalNested {
    value: i32,
}

// S2 might be a *foreign* type, i.e. declared in a different crate.
struct External<'a, T: Clone> {
    field1: &'a i64,
    field2: T,
    nested: ExternalNested,
}

struct ExternalNested {
    value: i32,
}

// This struct only exists for the sake of using `destinations` attribute with more than one
// type :)
struct ExternalNested2 {
    value: i32,
}

fn main() {
    let obj: Original<_> = Original {
        field1: &0,
        field2: String::from("lol"),
        nested: OriginalNested { value: 15 }
    };
    let cloned: External<_> = obj.clone_into();
    assert_eq!(obj.field1, cloned.field1);
    assert_eq!(obj.field2, cloned.field2);
    assert_eq!(obj.nested.value, cloned.nested.value);
    let cloned2 = Original::clone_from(&cloned);
    assert_eq!(cloned.field1, cloned2.field1);
    assert_eq!(cloned.field2, cloned2.field2);
    assert_eq!(obj, cloned2);
}

许可：MIT/Apache-2.0