55 lines
1.4 KiB
Markdown
55 lines
1.4 KiB
Markdown
# ptr_meta   [![Latest Version]][crates.io] [![License]][license path] [![requires: rustc 1.47+]][Rust 1.47]
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[Latest Version]: https://img.shields.io/crates/v/ptr_meta.svg
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[crates.io]: https://crates.io/crates/ptr_meta
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[License]: https://img.shields.io/badge/license-MIT-blue.svg
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[license path]: https://github.com/djkoloski/ptr_meta/blob/master/LICENSE
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[requires: rustc 1.47+]: https://img.shields.io/badge/rustc-1.47+-lightgray.svg
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[Rust 1.47]: https://blog.rust-lang.org/2020/10/08/Rust-1.47.html
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# ptr_meta
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A radioactive stabilization of the [`ptr_meta` RFC][rfc].
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[rfc]: https://rust-lang.github.io/rfcs/2580-ptr-meta.html
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## Usage
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### Sized types
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Sized types already have `Pointee` implemented for them, so most of the time you won't have to worry
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about them. However, trying to derive `Pointee` for a struct that may or may not have a DST as its
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last field will cause an implementation conflict with the automatic sized implementation.
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### `slice`s and `str`s
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These core types have implementations built in.
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### Structs with a DST as its last field
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You can derive `Pointee` for last-field DSTs:
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```rust
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use ptr_meta::Pointee;
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#[derive(Pointee)]
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struct Block<H, T> {
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header: H,
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elements: [T],
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}
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```
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### Trait objects
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You can generate a `Pointee` for trait objects:
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```rust
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use ptr_meta::pointee;
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// Generates Pointee for dyn Stringy
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#[pointee]
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trait Stringy {
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fn as_string(&self) -> String;
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}
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```
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