如何复制另一个结构的字段？

Question

Is there any crate or functionality that allows me to copy the fields from another structure?

Crate A

struct Product {
    name: String,
    sku: String,
    amount: i32,
}

Crate B

#[derive(copy_fields_from = "a::Product", InputObject)]
struct ProductApi {}

I have to expose several objects from another crate in an API that uses " #[derive(InputObject)] ". For that, I have to duplicate all the structures of the other structure. Is it possible to copy the fields of another structure? Perhaps using hypothetical syntax such as #[derive(copy_fields_from ="a::Product")] .

Answer 1

No, there is no way of doing this cleanly.

If you felt you had to do this, you'd need to write a build script that:

1. Located the source code of the target crate.
2. Parsed the source code using a crate like syn .
3. Located the types in question.
4. Output them again.

See also:

• How do I apply a macro attribute to a function defined in a separate module?
• Add Serialize attribute to type from third-party lib
• Is it possible for one struct to extend an existing struct, keeping all the fields?

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For your specific case, I'd advocate implementing whatever trait(s) by hand.