1 unstable release
0.1.0 | Mar 13, 2023 |
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#1006 in Procedural macros
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Derive Clone including clone_from
This crate offers a derive macro called CloneFrom
to derive Clone
with a specialized clone_from
implementation.
When deriving Clone
, Rust omits a specialized clone_from
implementation and defers to clone
instead.
This means that it can behave counter-intuitively, for example when it should reuse allocations, but does not.
This crate aims to be a drop-in replacement for deriving Clone
, but with a proper clone_from
implementation.
Example
#[derive(CloneFrom)]
struct MyStruct<T> {
name: String,
inner: Vec<T>,
}
Considerations
Adding a clone_from
implementation to all types in Rust seems to add a significant compile-time cost, which is why Rust does not provide this by default.
Many types do not benefit from a specialized clone_from
implementation, so it's important to add it when it brings a benefit.
License
Licensed under either of Apache License, Version 2.0 or MIT license at your option.
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this crate by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.
Dependencies
~1.5MB
~35K SLoC