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| #[feature(macro_rules)]; | |
| use std::hashmap::HashMap; | |
| macro_rules! lazy_init( | |
| ($(static ref $n:ident : $t:ty = $e:expr;)*) => ( | |
| $( | |
| struct $n; | |
| impl $n { | |
| #[allow(dead_code)] | |
| fn get(&self) -> &'static $t { | |
| use std::unstable::mutex::{Once, ONCE_INIT}; | |
| use std::cast::transmute; | |
| unsafe { | |
| static mut s: *$t = 0 as *$t; | |
| static mut ONCE: Once = ONCE_INIT; | |
| ONCE.doit(|| { | |
| s = transmute::<~$t, *$t>(~($e)); | |
| }); | |
| &*s | |
| } | |
| } | |
| } | |
| )* | |
| ) | |
| ) | |
| lazy_init!( | |
| static ref NUMBER: uint = times_two(3); | |
| static ref VEC: [uint, ..3] = [1, 2, 3]; | |
| static ref OWNED_STRING: ~str = ~"hello"; | |
| static ref HASHMAP: HashMap<uint, &'static str> = { | |
| let mut m = HashMap::new(); | |
| m.insert(0u, "abc"); | |
| m.insert(1, "def"); | |
| m.insert(2, "ghi"); | |
| m | |
| }; | |
| ) | |
| fn times_two(n: uint) -> uint { | |
| n * 2 | |
| } | |
| #[test] | |
| fn test_basic() { | |
| assert_eq!(OWNED_STRING.get(), &~"hello"); | |
| assert_eq!(NUMBER.get(), &6); | |
| assert!(HASHMAP.get().find(&1).is_some()); | |
| assert!(HASHMAP.get().find(&3).is_none()); | |
| assert_eq!(VEC.get().as_slice(), &[1, 2, 3]); | |
| } | |
| #[test] | |
| fn test_repeat() { | |
| assert_eq!(NUMBER.get(), &6); | |
| assert_eq!(NUMBER.get(), &6); | |
| assert_eq!(NUMBER.get(), &6); | |
| } |
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