You'll want to do destructuring assignment here. This means that you
take ownership of all fields in parallel:
fn into_test2(self) -> Test2 {
let Test1 { a, b } = self;
Test2 {
c: a,
d: b as f64
}
}
On Sun, Jan 26, 2014 at 9:32 AM, Vladimir Matveev
<[email protected]> wrote:
> Hi all,
>
> Consider this code:
>
> struct Test1 {
> a: ~str,
> b: f32,
> }
>
> struct Test2 {
> c: ~str,
> d: f64
> }
>
> impl Test1 {
> fn into_test2(self) -> Test2 {
> Test2 {
> c: self.a,
> d: self.b as f64
> }
> }
> }
>
>
> In into_test2() method I want to consume Test1 struct completely. But
> because ~str is not implicitly copyable, self.a is moved out of self,
> and on Test2.d field assignment I get the following error:
>
> main.rs:15:16: 15:21 error: use of partially moved value: `self`
> main.rs:15 d: self.b as f64
> ^~~~~
> main.rs:14:16: 14:22 note: `self.a` moved here because it has type
> `~str`, which is non-copyable (perhaps you meant to use clone()?)
> main.rs:14 c: self.a,
> ^~~~~~
>
> I know that I can, say, do self.a.clone() to avoid moving, but I don't
> want extra allocations. And it is also possible to reorder Test2
> fields assignments and it will work, but it won't if both fields are
> not copyable.
>
> So, the question is: how to correctly correctly move several pieces of
> data out from a struct without using clone()? Is it possible at all?
>
> Thanks,
> Vladimir.
> _______________________________________________
> Rust-dev mailing list
> [email protected]
> https://mail.mozilla.org/listinfo/rust-dev
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