Extending somebody's type

2

There are a few approaches:

  • if you want to implement a third-party trait B for Dialog, you can create a newtype

    struct MyDialog(Dialog);

    and then impl B for MyDialog

  • if you want to package additional data with Dialog, you'd create a new struct like this:

    struct DialogPlus {
    dialog: Dialog,
    extras: MyData,
}

  • if you just want to write your own functions that take a Dialog as receiver, so that you can call them with method syntax, you can write an extension trait:

    trait DialogExt {
    fn my_extra_method(&self) -> Foo;
}

impl DialogExt for Dialog {
    fn my_extra_method(&self) -> Foo {
        /* implementation goes here */
    }
}
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