That test is for multiple *items*, not statements.
For the moment, you just have to wrap the interior of a macro expanding
to an expression in a set of braces, so that it becomes a single statement.
macro_rules! my_print(
($a:expr, $b:expr) => (
{
println!("{:?}", a);
println!("{:?}", b);
}
);
)
Multi-statement macros are covered by
https://github.com/mozilla/rust/issues/10681 .
Huon
On 12/01/14 13:40, Ashish Myles wrote:
Rust 0.9 indicates that support for expansion of macros into multiple
statements is now supported, and the following example from the test
suite works for me.
https://github.com/mozilla/rust/blob/master/src/test/run-pass/macro-multiple-items.rs
However, I receive an error for the following code
#[feature(macro_rules)];
macro_rules! my_print(
($a:expr, $b:expr) => (
println!("{:?}", a);
println!("{:?}", b);
);
)
fn main() {
let a = 1;
let b = 2;
my_print!(a, b);
}
(Note that the ^~~~~~~ below points at println.)
$ rustc macro_ignores_second_line.rs <http://macro_ignores_second_line.rs>
macro_ignores_second_line.rs:6:9: 6:16 error: macro expansion ignores
token `println` and any following
macro_ignores_second_line.rs:6 <http://macro_ignores_second_line.rs:6>
println!("{:?}", b);
^~~~~~~
error: aborting due to previous error
task 'rustc' failed at 'explicit failure',
/home/marcianx/devel/rust/checkout/rust/src/libsyntax/diagnostic.rs:75
<http://diagnostic.rs:75>
task '<main>' failed at 'explicit failure',
/home/marcianx/devel/rust/checkout/rust/src/librustc/lib.rs:453
<http://lib.rs:453>
What's the right way to do this?
Ashish
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