2 releases
0.1.1 | Apr 13, 2019 |
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0.1.0 | Apr 12, 2019 |
#64 in #return
21KB
398 lines
Named Return
Declares a proc-macro that enables return types to be named.
Mostly re-defining structures from syn
for parsing.
The macro also:
- Declares the variables that were named as a prefix statement to the original function's body.
- Requires that the return syntax is similar to the input parameter
syntax.
- Requires parentheses.
Example
#![feature(proc_macro_hygiene)]
use named_return::named_return;
#
# #[derive(Debug, PartialEq, Eq)]
# pub struct A;
# #[derive(Debug, PartialEq, Eq)]
# pub struct B;
named_return!(
fn f() -> (a: A, b: B) {
a = A;
b = B;
(a, b)
});
assert_eq!(f(), (A, B));
Note
The intended syntax were to be used with a proc-macro-attr, such as:
#[named_return]
fn f() -> (a: A, b: B) {
a = A;
b = B;
(a, b)
}
But it seems that Rust parses the original function syntax before executing the proc-macro-attr and so it refuses the invalid syntax.
This is a draft and is based on this suggestion: https://github.com/rust-lang/rfcs/issues/2638
Dependencies
~2MB
~46K SLoC