44 lines
1022 B
Rust
44 lines
1022 B
Rust
#![feature(macro_metavar_expr)]
|
|
|
|
macro_rules! a {
|
|
( $( { $( [ $( ( $( $foo:ident )* ) )* ] )* } )* ) => {
|
|
(
|
|
${count(foo, 0)},
|
|
${count(foo, 10)},
|
|
//~^ ERROR depth parameter on meta-variable expression `count` must be less than 4
|
|
)
|
|
};
|
|
}
|
|
|
|
macro_rules! b {
|
|
( $( { $( [ $( $foo:ident )* ] )* } )* ) => {
|
|
(
|
|
$( $( $(
|
|
${ignore(foo)}
|
|
${index(0)},
|
|
${index(10)},
|
|
//~^ ERROR depth parameter on meta-variable expression `index` must be less than 3
|
|
)* )* )*
|
|
)
|
|
};
|
|
}
|
|
|
|
macro_rules! c {
|
|
( $( { $( $foo:ident )* } )* ) => {
|
|
(
|
|
$( $(
|
|
${ignore(foo)}
|
|
${length(0)}
|
|
${length(10)}
|
|
//~^ ERROR depth parameter on meta-variable expression `length` must be less than 2
|
|
)* )*
|
|
)
|
|
};
|
|
}
|
|
|
|
fn main() {
|
|
a!( { [ (a) ] [ (b c) ] } );
|
|
b!( { [ a b ] } );
|
|
c!({ a });
|
|
}
|