1 //! impl bool {} 2 3 #[lang = "bool"] 4 impl bool { 5 /// Returns `Some(t)` if the `bool` is [`true`](../std/keyword.true.html), 6 /// or `None` otherwise. 7 /// 8 /// # Examples 9 /// 10 /// ``` 11 /// #![feature(bool_to_option)] 12 /// 13 /// assert_eq!(false.then_some(0), None); 14 /// assert_eq!(true.then_some(0), Some(0)); 15 /// ``` 16 #[unstable(feature = "bool_to_option", issue = "80967")] 17 #[inline] then_some<T>(self, t: T) -> Option<T>18 pub fn then_some<T>(self, t: T) -> Option<T> { 19 if self { Some(t) } else { None } 20 } 21 22 /// Returns `Some(f())` if the `bool` is [`true`](../std/keyword.true.html), 23 /// or `None` otherwise. 24 /// 25 /// # Examples 26 /// 27 /// ``` 28 /// assert_eq!(false.then(|| 0), None); 29 /// assert_eq!(true.then(|| 0), Some(0)); 30 /// ``` 31 #[stable(feature = "lazy_bool_to_option", since = "1.50.0")] 32 #[inline] then<T, F: FnOnce() -> T>(self, f: F) -> Option<T>33 pub fn then<T, F: FnOnce() -> T>(self, f: F) -> Option<T> { 34 if self { Some(f()) } else { None } 35 } 36 } 37