From fe87063a187f65ce2dbc7b338cc88c1ee04049bd Mon Sep 17 00:00:00 2001 From: Maybe Waffle Date: Mon, 20 Mar 2023 18:23:03 +0000 Subject: [PATCH 1/2] Add `minmax*` functions to `core::cmp` --- library/core/src/cmp.rs | 85 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 85 insertions(+) diff --git a/library/core/src/cmp.rs b/library/core/src/cmp.rs index 3c127efb390ae..98bff552ac6fd 100644 --- a/library/core/src/cmp.rs +++ b/library/core/src/cmp.rs @@ -1266,6 +1266,91 @@ pub fn max_by_key K, K: Ord>(v1: T, v2: T, mut f: F) -> T { max_by(v1, v2, |v1, v2| f(v1).cmp(&f(v2))) } +/// Compares and sorts two values, returning minimum and maximum. +/// +/// Returns `[v1, v2]` if the comparison determines them to be equal. +/// +/// # Examples +/// +/// ``` +/// #![feature(cmp_minmax)] +/// use std::cmp; +/// +/// assert_eq!(cmp::minmax(1, 2), [1, 2]); +/// assert_eq!(cmp::minmax(2, 2), [2, 2]); +/// +/// // You can destructure the result using array patterns +/// let [min, max] = cmp::minmax(42, 17); +/// assert_eq!(min, 17); +/// assert_eq!(max, 42); +/// ``` +#[inline] +#[must_use] +#[unstable(feature = "cmp_minmax", issue = "none")] +pub fn minmax(v1: T, v2: T) -> [T; 2] +where + T: Ord, +{ + if v1 <= v2 { [v1, v2] } else { [v2, v1] } +} + +/// Returns minimum and maximum values with respect to the specified comparison function. +/// +/// Returns `[v1, v2]` if the comparison determines them to be equal. +/// +/// # Examples +/// +/// ``` +/// #![feature(cmp_minmax)] +/// use std::cmp; +/// +/// assert_eq!(cmp::minmax_by(-2, 1, |x: &i32, y: &i32| x.abs().cmp(&y.abs())), [1, -2]); +/// assert_eq!(cmp::minmax_by(-2, 2, |x: &i32, y: &i32| x.abs().cmp(&y.abs())), [-2, 2]); +/// +/// // You can destructure the result using array patterns +/// let [min, max] = cmp::minmax_by(-42, 17, |x: &i32, y: &i32| x.abs().cmp(&y.abs())); +/// assert_eq!(min, 17); +/// assert_eq!(max, -42); +/// ``` +#[inline] +#[must_use] +#[unstable(feature = "cmp_minmax", issue = "none")] +pub fn minmax_by(v1: T, v2: T, compare: F) -> [T; 2] +where + F: FnOnce(&T, &T) -> Ordering, +{ + if compare(&v1, &v2).is_le() { [v1, v2] } else { [v2, v1] } +} + +/// Returns minimum and maximum values with respect to the specified key function. +/// +/// Returns `[v1, v2]` if the comparison determines them to be equal. +/// +/// # Examples +/// +/// ``` +/// #![feature(cmp_minmax)] +/// use std::cmp; +/// +/// assert_eq!(cmp::minmax_by_key(-2, 1, |x: &i32| x.abs()), [1, -2]); +/// assert_eq!(cmp::minmax_by_key(-2, 2, |x: &i32| x.abs()), [-2, 2]); +/// +/// // You can destructure the result using array patterns +/// let [min, max] = cmp::minmax_by_key(-42, 17, |x: &i32| x.abs()); +/// assert_eq!(min, 17); +/// assert_eq!(max, -42); +/// ``` +#[inline] +#[must_use] +#[unstable(feature = "cmp_minmax", issue = "none")] +pub fn minmax_by_key(v1: T, v2: T, mut f: F) -> [T; 2] +where + F: FnMut(&T) -> K, + K: Ord, +{ + minmax_by(v1, v2, |v1, v2| f(v1).cmp(&f(v2))) +} + // Implementation of PartialEq, Eq, PartialOrd and Ord for primitive types mod impls { use crate::cmp::Ordering::{self, Equal, Greater, Less}; From 0c3e0abbf8cff8cf0765c41f8d49000bc467d642 Mon Sep 17 00:00:00 2001 From: Maybe Waffle Date: Mon, 18 Sep 2023 16:21:03 +0000 Subject: [PATCH 2/2] Fill-in tracking issue for `feature(cmp_minmax)` --- library/core/src/cmp.rs | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/library/core/src/cmp.rs b/library/core/src/cmp.rs index 98bff552ac6fd..c8d1b1a8825dc 100644 --- a/library/core/src/cmp.rs +++ b/library/core/src/cmp.rs @@ -1286,7 +1286,7 @@ pub fn max_by_key K, K: Ord>(v1: T, v2: T, mut f: F) -> T { /// ``` #[inline] #[must_use] -#[unstable(feature = "cmp_minmax", issue = "none")] +#[unstable(feature = "cmp_minmax", issue = "115939")] pub fn minmax(v1: T, v2: T) -> [T; 2] where T: Ord, @@ -1314,7 +1314,7 @@ where /// ``` #[inline] #[must_use] -#[unstable(feature = "cmp_minmax", issue = "none")] +#[unstable(feature = "cmp_minmax", issue = "115939")] pub fn minmax_by(v1: T, v2: T, compare: F) -> [T; 2] where F: FnOnce(&T, &T) -> Ordering, @@ -1342,7 +1342,7 @@ where /// ``` #[inline] #[must_use] -#[unstable(feature = "cmp_minmax", issue = "none")] +#[unstable(feature = "cmp_minmax", issue = "115939")] pub fn minmax_by_key(v1: T, v2: T, mut f: F) -> [T; 2] where F: FnMut(&T) -> K,