1 /// A macro for defining `#[cfg]` if-else statements.
3 /// This is similar to the `if/elif` C preprocessor macro by allowing definition
4 /// of a cascade of `#[cfg]` cases, emitting the implementation which matches
7 /// This allows you to conveniently provide a long list `#[cfg]`'d blocks of code
8 /// without having to rewrite each clause multiple times.
11 if #[cfg($($meta:meta),*)] { $($it:item)* }
17 $( ( ($($meta),*) ($($it)*) ), )*
23 macro_rules! __cfg_if_items {
24 (($($not:meta,)*) ; ) => {};
25 (($($not:meta,)*) ; ( ($($m:meta),*) ($($it:item)*) ), $($rest:tt)*) => {
26 __cfg_if_apply! { cfg(all(not(any($($not),*)), $($m,)*)), $($it)* }
27 __cfg_if_items! { ($($not,)* $($m,)*) ; $($rest)* }
31 macro_rules! __cfg_if_apply {
32 ($m:meta, $($it:item)*) => {