iproduct rejects trailing comma

[ijackson]

To reproduce:

use itertools::iproduct;

fn main() {
    for e in iproduct!(
        [1,2],
        [3,4],
    ) {
        println!("{e:?}");
    }
}

Expected output: it works (printing 4 lines of output).

Actual output:

error: unexpected end of macro invocation
   --> src/main.rs:6:15
    |
6   |         [3,4],
    |               ^ missing tokens in macro arguments
    |
note: while trying to match meta-variable `$K:expr`
   --> /playground/.cargo/registry/src/index.crates.io-6f17d22bba15001f/itertools-0.12.0/src/lib.rs:259:26
    |
259 |     ($I:expr, $J:expr, $($K:expr),+) => (
    |                          ^^^^^^^

chain! and izip! are fine.

Removing the trailing comma works:

use itertools::iproduct;

fn main() {
    for e in iproduct!(
        [1,2],
        [3,4]
    ) {
        println!("{e:?}");
    }
}

[Philippe-Cholet]

I agree.

[Philippe-Cholet]

Add $(,)? at the end of each pattern of the macro would solve this.