qualifier_attr 0.1.5

Procedural macro attributes for adding "qualifiers" (pub, async, unsafe, extern "C",...) to various items.
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# qualifier_attr


[![Latest Version](https://img.shields.io/crates/v/qualifier_attr.svg)][`qualifier_attr`]
[![Downloads](https://img.shields.io/crates/d/qualifier_attr.svg)][`qualifier_attr`]
[![Documentation](https://docs.rs/qualifier_attr/badge.svg)][`qualifier_attr`/docs]
[![License](https://img.shields.io/crates/l/qualifier_attr.svg)][`qualifier_attr`/license]
[![Dependency Status](https://deps.rs/repo/github/JohnScience/qualifier_attr/status.svg)][`qualifier_attr`/dep_status]

> Procedural macro attributes for adding "qualifiers" to various items.

At the moment, the crate supports only functions with the following "qualifiers":

* `pub`, `pub(crate)`, ... - visibility qualifiers
* `async` - async qualifier
* `unsafe` - unsafe qualifier
* `const` - const qualifier
* `extern "ABI"` - ABI qualifier

as well as structures and named fields within structs  with `pub`, `pub(crate)`, etc visibility qualifiers.

Modules can't be supported due to hygiene issues.

## Examples


```rust
use qualifier_attr::fn_qualifiers;

// We can add a qualifier to a function
// with an attribute.
#[fn_qualifiers(const)]

fn const_fn() -> u32 { 42 }

const CONST_RES: u32 = const_fn();

// It's not so impresive on its own
// but with cfg_attr it can be conditional.

#[cfg_attr(feature = "extern_c", no_mangle, fn_qualifiers(pub, extern "C"))]

fn extern_c_fn() -> u32 { 42 }
```

Learn more about `cfg_attr` [here](https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute).

## Similar crates


* [`const_fn`](https://crates.io/crates/const_fn).

## License


<sup>
Licensed under either of <a href="LICENSE-APACHE">Apache License, Version
2.0</a> or <a href="LICENSE-MIT">MIT license</a> at your option.
</sup>

<br>

<sub>
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.
</sub>

[`qualifier_attr`]: https://crates.io/crates/qualifier_attr
[`qualifier_attr`/docs]: https://docs.rs/qualifier_attr
[`qualifier_attr`/license]: https://github.com/JohnScience/qualifier_attr#license
[`qualifier_attr`/dep_status]: https://deps.rs/repo/github/JohnScience/qualifier_attr