#[const_fn]

An attribute for easy generation of a const function with conditional compilations.

Usage

Add this to your Cargo.toml:

toml [dependencies] const_fn = "0.1"

and this to your crate root:

```rust

[macro_use]

extern crate const_fn; ```

Examples

When using like the following functions to control unstable features:

toml [features] const = []

It can be written as follows:

```rust

![cfgattr(feature = "const", feature(constfn, constvecnew))]

[const_fn(feature = "const")]

pub const fn empty_vec() -> Vec { Vec::new() } ```

Code like this will be generated:

```rust

![cfgattr(feature = "const", feature(constfn, constvecnew))]

[cfg(feature = "const")]

pub const fn empty_vec() -> Vec { Vec::new() }

[cfg(not(feature = "const"))]

pub fn empty_vec() -> Vec { Vec::new() } ```

See [test_suite] for more examples.

Rust Version

The current minimum required Rust version is 1.30.

License

Licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.