3 unstable releases
0.1.1 | Aug 30, 2019 |
---|---|
0.1.0 | Aug 30, 2019 |
0.0.1 | Aug 30, 2019 |
#12 in #zig
24 downloads per month
Used in import_file_macro
11KB
183 lines
Lightweight compile-time expression evaluation.
This crate is inspired by Zig's comptime
.
The expression returned by the contents of the comptime macro invocation will be parsed as Rust source code and inserted back into the call site.
tl;dr: comptime!
gives you no-context anonynmous proc macros.
Example
#![feature(proc_macro_hygiene)]
fn main() {
println!(concat!(
"The program was compiled on ",
comptime::comptime! {
chrono::Utc::now().format("%Y-%m-%d").to_string()
},
"."
)); // The program was compiled on 2019-08-30.
}
Limitations
Unlike the real comptime
, comptime!
does not have access to the scope in which it is invoked.
The code in comptime!
is run as its own script.
Though, technically, you could interpolate static values using quote!
.
Also, comptime!
requires you to run cargo build
at least once before cargo (clippy|check)
will work since comptime!
does not compile dependencies.
Contributing
Please do!
Ideally, rustc
would also have (real) comptime
which would have access to type information and other static values.
In the meantime, this should be a nice way to approximate and experiment with such functionality.
Dependencies
~1.5MB
~34K SLoC