| /// A macro for defining #[cfg] if-else statements. |
| /// |
| /// This is similar to the `if/elif` C preprocessor macro by allowing definition |
| /// of a cascade of `#[cfg]` cases, emitting the implementation which matches |
| /// first. |
| /// |
| /// This allows you to conveniently provide a long list #[cfg]'d blocks of code |
| /// without having to rewrite each clause multiple times. |
| macro_rules! cfg_if { |
| ($( |
| if #[cfg($($meta:meta),*)] { $($it:item)* } |
| ) else * else { |
| $($it2:item)* |
| }) => { |
| __cfg_if_items! { |
| () ; |
| $( ( ($($meta),*) ($($it)*) ), )* |
| ( () ($($it2)*) ), |
| } |
| } |
| } |
| |
| macro_rules! __cfg_if_items { |
| (($($not:meta,)*) ; ) => {}; |
| (($($not:meta,)*) ; ( ($($m:meta),*) ($($it:item)*) ), $($rest:tt)*) => { |
| __cfg_if_apply! { cfg(all(not(any($($not),*)), $($m,)*)), $($it)* } |
| __cfg_if_items! { ($($not,)* $($m,)*) ; $($rest)* } |
| } |
| } |
| |
| macro_rules! __cfg_if_apply { |
| ($m:meta, $($it:item)*) => { |
| $(#[$m] $it)* |
| } |
| } |
| |
| macro_rules! s { |
| ($($(#[$attr:meta])* pub struct $i:ident { $($field:tt)* })*) => ($( |
| __item! { |
| #[repr(C)] |
| $(#[$attr])* |
| pub struct $i { $($field)* } |
| } |
| impl ::dox::Copy for $i {} |
| impl ::dox::Clone for $i { |
| fn clone(&self) -> $i { *self } |
| } |
| )*) |
| } |
| |
| macro_rules! f { |
| ($(pub fn $i:ident($($arg:ident: $argty:ty),*) -> $ret:ty { |
| $($body:stmt);* |
| })*) => ($( |
| #[inline] |
| #[cfg(not(dox))] |
| pub unsafe extern fn $i($($arg: $argty),*) -> $ret { |
| $($body);* |
| } |
| |
| #[cfg(dox)] |
| #[allow(dead_code)] |
| pub unsafe extern fn $i($($arg: $argty),*) -> $ret { |
| loop {} |
| } |
| )*) |
| } |
| |
| macro_rules! __item { |
| ($i:item) => ($i) |
| } |
| |
| #[cfg(test)] |
| mod tests { |
| cfg_if! { |
| if #[cfg(test)] { |
| use std::option::Option as Option2; |
| fn works1() -> Option2<u32> { Some(1) } |
| } else { |
| fn works1() -> Option<u32> { None } |
| } |
| } |
| |
| cfg_if! { |
| if #[cfg(foo)] { |
| fn works2() -> bool { false } |
| } else if #[cfg(test)] { |
| fn works2() -> bool { true } |
| } else { |
| fn works2() -> bool { false } |
| } |
| } |
| |
| cfg_if! { |
| if #[cfg(foo)] { |
| fn works3() -> bool { false } |
| } else { |
| fn works3() -> bool { true } |
| } |
| } |
| |
| #[test] |
| fn it_works() { |
| assert!(works1().is_some()); |
| assert!(works2()); |
| assert!(works3()); |
| } |
| } |