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Rollup merge of #93051 - m-ou-se:is-some-with, r=yaahc

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Add Option::is_some_with and Result::is_{ok,err}_with

See https://github.com/rust-lang/rust/issues/62358#issuecomment-1015827777
This commit is contained in:
Matthias Krüger 2022-01-19 10:42:20 +01:00 committed by GitHub
commit d5bc168d65
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23
library/core/src/option.rs
View File

@ -551,6 +551,29 @@ impl<T> Option<T> {
matches!(*self, Some(_))
}
/// Returns `true` if the option is a [`Some`] wrapping a value matching the predicate.
///
/// # Examples
///
/// ```
/// #![feature(is_some_with)]
///
/// let x: Option<u32> = Some(2);
/// assert_eq!(x.is_some_with(|&x| x > 1), true);
///
/// let x: Option<u32> = Some(0);
/// assert_eq!(x.is_some_with(|&x| x > 1), false);
///
/// let x: Option<u32> = None;
/// assert_eq!(x.is_some_with(|&x| x > 1), false);
/// ```
#[must_use]
#[inline]
#[unstable(feature = "is_some_with", issue = "93050")]
pub fn is_some_with(&self, f: impl FnOnce(&T) -> bool) -> bool {
matches!(self, Some(x) if f(x))
}
/// Returns `true` if the option is a [`None`] value.
///
/// # Examples

47
library/core/src/result.rs
View File

@ -542,6 +542,29 @@ impl<T, E> Result<T, E> {
matches!(*self, Ok(_))
}
/// Returns `true` if the result is [`Ok`] wrapping a value matching the predicate.
///
/// # Examples
///
/// ```
/// #![feature(is_some_with)]
///
/// let x: Result<u32, &str> = Ok(2);
/// assert_eq!(x.is_ok_with(|&x| x > 1), true);
///
/// let x: Result<u32, &str> = Ok(0);
/// assert_eq!(x.is_ok_with(|&x| x > 1), false);
///
/// let x: Result<u32, &str> = Err("hey");
/// assert_eq!(x.is_ok_with(|&x| x > 1), false);
/// ```
#[must_use]
#[inline]
#[unstable(feature = "is_some_with", issue = "93050")]
pub fn is_ok_with(&self, f: impl FnOnce(&T) -> bool) -> bool {
matches!(self, Ok(x) if f(x))
}
/// Returns `true` if the result is [`Err`].
///
/// # Examples
@ -563,6 +586,30 @@ impl<T, E> Result<T, E> {
!self.is_ok()
}
/// Returns `true` if the result is [`Err`] wrapping a value matching the predicate.
///
/// # Examples
///
/// ```
/// #![feature(is_some_with)]
/// use std::io::{Error, ErrorKind};
///
/// let x: Result<u32, Error> = Err(Error::new(ErrorKind::NotFound, "!"));
/// assert_eq!(x.is_err_with(|x| x.kind() == ErrorKind::NotFound), true);
///
/// let x: Result<u32, Error> = Err(Error::new(ErrorKind::PermissionDenied, "!"));
/// assert_eq!(x.is_err_with(|x| x.kind() == ErrorKind::NotFound), false);
///
/// let x: Result<u32, Error> = Ok(123);
/// assert_eq!(x.is_err_with(|x| x.kind() == ErrorKind::NotFound), false);
/// ```
#[must_use]
#[inline]
#[unstable(feature = "is_some_with", issue = "93050")]
pub fn is_err_with(&self, f: impl FnOnce(&E) -> bool) -> bool {
matches!(self, Err(x) if f(x))
}
/////////////////////////////////////////////////////////////////////////
// Adapter for each variant
/////////////////////////////////////////////////////////////////////////