Provides cfg_match and cfg_match_with_default macros

Based on: cfg-if

Macros to ergonomically define an item depending on a large number of #[cfg] parameters. Structured like a match block, the first matching branch is the item that gets emitted.

#[macro_use]
extern crate cfg_match;

fn works() -> bool {
    cfg_match! {
         #[cfg(foo)] => { false },
         #[cfg(test)] => { true }
    }
}

fn works_with_default() -> bool {
    cfg_match_with_default! {
        #[cfg(foo)] => { false },
        #[cfg(bar)] => { false },
        _ => { true }
    }
}

#[test]
fn smoke() {
    assert!(works());
    assert!(works_with_default());
}

When using cfg_match and no match is possible you get a compilation error:

fn does_not_compile() -> bool {
    cfg_match! {
        #[cfg(foo)] => { false },
        #[cfg(bar)] => { false }
    }
}

You get the following error:

error: cfg_match: #[cfg(<check desired feature case>)] was not implemented.
  --> tests/xcrate.rs:45:5
   |
45 | /     cfg_match! {
46 | |         #[cfg(foo)] => { false },
...  |
51 | |         }
52 | |     }
   | |_____^
   |
   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)

This project is 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.

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