fast_able/
defer.rs

1/// Guard structure for defer
2/// defer 的守卫结构体
3pub struct Guard<F: FnMut()>(pub Option<F>);
4
5impl<F: FnMut()> Drop for Guard<F> {
6    fn drop(&mut self) {
7        if let Some(mut f) = (self.0).take() {
8            f()
9        }
10    }
11}
12
13/// Defers evaluation of a block of code until the end of the scope.
14/// Sort of LIFO(last-in, first-out queue)
15/// If you encounter references to resources that cannot mut more than 2 times, try nesting RefCell and then use.borrow() and.borrow_mut().
16///
17/// 延迟代码块的执行直到作用域结束。
18/// 类似于 LIFO（后进先出队列）
19/// 如果遇到不能 mut 超过 2 次的资源引用，尝试嵌套 RefCell 然后使用 .borrow() 和 .borrow_mut()。
20///
21/// for example:
22/// ```
23///  use dark_std::defer;
24///  //LIFO, so it will print: guard: 3  guard: 2   guard: 1
25///  fn main(){
26///     defer!({
27///        println!("guard: 1");
28///        });
29///     defer!(||{
30///        println!("guard: 2");
31///        });
32///     defer!{
33///        println!("guard: 3");
34///     }
35/// }
36/// ```
37///
38///
39#[macro_export]
40macro_rules! defer {
41    ($func:block) => {
42       let _guard = $crate::defer::Guard(Some( ||$func));
43    };
44    ($func:expr) => {
45        let _guard = $crate::defer::Guard(Some($func));
46    };
47    { $($func:expr$(;)?)+ } => {
48       let _guard = $crate::defer::Guard(Some( ||{$($func;)+}));
49    }
50}
51
52#[cfg(test)]
53mod test {
54    #[test]
55    fn test_defer() {
56        defer!(|| {
57            println!("defer");
58        });
59    }
60}
fast_able/defer.rs

fast_able/
defer.rs
