iota.rs

#![feature(macro_rules)]

macro_rules! iota(
    ($($thing:expr),+) => (iota_expr!(1, $($thing),*));
    ($($thing:pat),+) => (iota_pat!(1, $($thing),*));
    () => (());
)

macro_rules! iota_expr(
    ($id:expr, $head:expr, $($tail:expr),*) => ({
        println!("expr {}", $id); iota_expr!($id+1, $($tail),*);
    });
    ($id:expr, $last:expr) => ({ println!("expr {}", $id); });
)

macro_rules! iota_pat(
    ($id:expr, $head:pat, $($tail:pat),*) => ({
        println!("pat {}", $id); iota_pat!($id+1, $($tail),*);
    });
    ($id:expr, $last:pat) => ({ println!("pat {}", $id); });
)

fn test_iota() {
    println!("empty test");
    iota!();

    // expr
    println!("expr test");
    iota!(9);
    iota!(9,9,9);

    // ident - matched by expr
    println!("ident test");
    iota!(Nine);
    iota!(Nine,Nine,Nine);

    // ty - matched by expr
    println!("ty test");
    iota!(Option::<int>);
    iota!(Option::<int>,Option::<int>,Option::<int>);

    // block - matched by expr
    println!("block test");
    iota!({9;9});
    iota!({9;9},{9;9},{9;9});

    // pat
    println!("pat test");
    iota!(foo @ _);
    iota!(foo @ _,foo @ _,foo @ _);
}

fn main() {
    test_iota();
}