9 unstable releases
0.5.1 | Oct 5, 2024 |
---|---|
0.5.0 | Feb 29, 2024 |
0.4.1 | Jan 24, 2024 |
0.4.0 | Nov 3, 2023 |
0.1.1 | Mar 30, 2022 |
#81 in Rust patterns
268,598 downloads per month
Used in 424 crates
(18 directly)
14KB
104 lines
constcat
std::concat!
with support for const
variables and expressions.
Works on stable Rust ✨.
🚀 Getting started
Add constcat
to your Cargo manifest.
cargo add constcat
Import the macro using the following.
use constcat::concat;
🤸 Usage
String slices
concat!
works exactly like std::concat!
, concatenating &str
literals into a static string slice, except you can now pass variables and
constant expressions.
const CRATE_NAME: &str = env!("CARGO_PKG_NAME");
const CRATE_VERSION: &str = env!("CARGO_PKG_VERSION");
const fn tada() -> &'static str { "🎉" }
const VERSION: &str = concat!(CRATE_NAME, " ", CRATE_VERSION, tada());
Byte slices
concat_bytes!
works similarly to concat!
, concatenating const
&[u8]
expressions and literals into a static byte slice.
const VERSION: u32 = 1;
const fn entries() -> &'static [u8] { b"example" }
const HEADER: &[u8] = concat_bytes!(&VERSION.to_le_bytes(), entries());
T
slices
concat_slices!
is the underlying macro used for both of the above, this
can be used to concatenate const
&[T]
expressions into a static
slice.
This macro requires the type of slice to be specified in the form [T]:
before the comma separated expressions.
const MAGIC: &[i32; 4] = &[1, 3, 3, 7];
const VERSION: i32 = 1;
const HEADER: &[i32] = concat_slices!([i32]: MAGIC, &[0, VERSION]);
const PRIMARIES: &'static [(u8, u8, u8)] = &[(255, 0, 0), (0, 255, 0), (0, 0, 255)];
const SECONDARIES: &'static [(u8, u8, u8)] = &[(255, 255, 0), (255, 0, 255), (0, 255, 255)];
const COLORS: &[(u8, u8, u8)] = concat_slices!([(u8, u8, u8)]: PRIMARIES, SECONDARIES);
MSRV
This crate supports Rust 1.60 and above.
License
This project is distributed under the terms of both the MIT license and the Apache License (Version 2.0).
See LICENSE-APACHE and LICENSE-MIT for details.