1 unstable release
0.1.0 | May 13, 2019 |
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#1194 in Procedural macros
160KB
3.5K
SLoC
Sonic Spin
Declares a macro that turns the ::()
postfix operator into a general postfix operator.
Mostly by re-defining structures from the syn
for parsing.
Example
#![feature(proc_macro_hygiene)]
use sonic_spin::sonic_spin;
sonic_spin! {
let res = 0::(match) {
x => x + 2
}::(match) {
x => x + 10
};
assert_eq!(res, 12);
let mut acc = 0;
(0..3)::(for _ in) {
acc += 1;
};
assert_eq!(acc, 3);
}
See tests/
for further examples.
Motivation
Given some of the many discussions regarding the await
syntax and the resulting possibility of general postfix operators, this crate explores such possibility with the "sonic-spin" operator (::()
).
If the await syntax turned out to be "prefix await" await expr
, then this crate would enable the syntax expr::(await)
similarly to the ?
postfix operator.
Some of the mentioned discussions:
- https://internals.rust-lang.org/t/idea-universal-pipelining-a-k-a-making-await-generic/9973
- https://github.com/rust-lang/rfcs/pull/2442
Further work
- Explore if/how postfix macros could work.
- Test with the await case (even if it's already a postfix operator).
- Explore auto bracing addition.
Pipe operations
For piped operations, see the tests/common.rs::Pipe
trait and it's usage in tests/if.rs::if_pipe
function. ie. sonic-spin is not required for such operations.
Notes
This is a draft and is based on this suggestion:
https://github.com/rust-lang/rfcs/issues/2698
Dependencies
~1.5MB
~29K SLoC