bool.rs.html -- source
Description: Source to the Rust file `library/core/src/bool.rs`.
Keywords: rust, rustlang, rust-lang

     1
     2
     3
     4
     5
     6
     7
     8
     9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    31
    32
    33
    34
    35
    36

    //! impl bool {}

    #[lang = "bool"]
    impl bool {
        /// Returns `Some(t)` if the `bool` is `true`, or `None` otherwise.
        ///
        /// # Examples
        ///
        /// ```
        /// #![feature(bool_to_option)]
        ///
        /// assert_eq!(false.then_some(0), None);
        /// assert_eq!(true.then_some(0), Some(0));
        /// ```
        #[unstable(feature = "bool_to_option", issue = "64260")]
        #[inline]
        pub fn then_some<T>(self, t: T) -> Option<T> {
            if self { Some(t) } else { None }
        }

        /// Returns `Some(f())` if the `bool` is `true`, or `None` otherwise.
        ///
        /// # Examples
        ///
        /// ```
        /// #![feature(bool_to_option)]
        ///
        /// assert_eq!(false.then(|| 0), None);
        /// assert_eq!(true.then(|| 0), Some(0));
        /// ```
        #[unstable(feature = "bool_to_option", issue = "64260")]
        #[inline]
        pub fn then<T, F: FnOnce() -> T>(self, f: F) -> Option<T> {
            if self { Some(f()) } else { None }
        }
    }