diff options
| -rw-r--r-- | library/core/src/option.rs | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/library/core/src/option.rs b/library/core/src/option.rs index e253cfd2822..d90b9cdb4b5 100644 --- a/library/core/src/option.rs +++ b/library/core/src/option.rs @@ -654,6 +654,32 @@ impl<T> Option<T> { !self.is_some() } + /// Returns `true` if the option is a [`None`] or the value inside of it matches a predicate. + /// + /// # Examples + /// + /// ``` + /// #![feature(is_none_or)] + /// + /// let x: Option<u32> = Some(2); + /// assert_eq!(x.is_none_or(|x| x > 1), true); + /// + /// let x: Option<u32> = Some(0); + /// assert_eq!(x.is_none_or(|x| x > 1), false); + /// + /// let x: Option<u32> = None; + /// assert_eq!(x.is_none_or(|x| x > 1), true); + /// ``` + #[must_use] + #[inline] + #[unstable(feature = "is_none_or", issue = "none")] + pub fn is_none_or(self, f: impl FnOnce(T) -> bool) -> bool { + match self { + None => true, + Some(x) => f(x), + } + } + ///////////////////////////////////////////////////////////////////////// // Adapter for working with references ///////////////////////////////////////////////////////////////////////// |