1344 lines
39 KiB
Rust
1344 lines
39 KiB
Rust
//! Functionality for ordering and comparison.
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//!
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//! This module contains various tools for ordering and comparing values. In
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//! summary:
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//!
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//! * [`Eq`] and [`PartialEq`] are traits that allow you to define total and
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//! partial equality between values, respectively. Implementing them overloads
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//! the `==` and `!=` operators.
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//! * [`Ord`] and [`PartialOrd`] are traits that allow you to define total and
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//! partial orderings between values, respectively. Implementing them overloads
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//! the `<`, `<=`, `>`, and `>=` operators.
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//! * [`Ordering`] is an enum returned by the main functions of [`Ord`] and
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//! [`PartialOrd`], and describes an ordering.
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//! * [`Reverse`] is a struct that allows you to easily reverse an ordering.
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//! * [`max`] and [`min`] are functions that build off of [`Ord`] and allow you
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//! to find the maximum or minimum of two values.
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//!
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//! For more details, see the respective documentation of each item in the list.
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//!
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//! [`max`]: Ord::max
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//! [`min`]: Ord::min
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#![stable(feature = "rust1", since = "1.0.0")]
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use self::Ordering::*;
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/// Trait for equality comparisons which are [partial equivalence
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/// relations](https://en.wikipedia.org/wiki/Partial_equivalence_relation).
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///
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/// This trait allows for partial equality, for types that do not have a full
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/// equivalence relation. For example, in floating point numbers `NaN != NaN`,
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/// so floating point types implement `PartialEq` but not [`Eq`](Eq).
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///
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/// Formally, the equality must be (for all `a`, `b` and `c`):
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///
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/// - symmetric: `a == b` implies `b == a`; and
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/// - transitive: `a == b` and `b == c` implies `a == c`.
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///
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/// Note that these requirements mean that the trait itself must be implemented
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/// symmetrically and transitively: if `T: PartialEq<U>` and `U: PartialEq<V>`
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/// then `U: PartialEq<T>` and `T: PartialEq<V>`.
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///
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/// ## Derivable
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///
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/// This trait can be used with `#[derive]`. When `derive`d on structs, two
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/// instances are equal if all fields are equal, and not equal if any fields
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/// are not equal. When `derive`d on enums, each variant is equal to itself
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/// and not equal to the other variants.
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///
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/// ## How can I implement `PartialEq`?
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///
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/// `PartialEq` only requires the [`eq`] method to be implemented; [`ne`] is defined
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/// in terms of it by default. Any manual implementation of [`ne`] *must* respect
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/// the rule that [`eq`] is a strict inverse of [`ne`]; that is, `!(a == b)` if and
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/// only if `a != b`.
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///
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/// Implementations of `PartialEq`, [`PartialOrd`], and [`Ord`] *must* agree with
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/// each other. It's easy to accidentally make them disagree by deriving some
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/// of the traits and manually implementing others.
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///
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/// An example implementation for a domain in which two books are considered
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/// the same book if their ISBN matches, even if the formats differ:
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///
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/// ```
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/// enum BookFormat {
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/// Paperback,
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/// Hardback,
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/// Ebook,
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/// }
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///
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/// struct Book {
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/// isbn: i32,
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/// format: BookFormat,
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/// }
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///
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/// impl PartialEq for Book {
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/// fn eq(&self, other: &Self) -> bool {
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/// self.isbn == other.isbn
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/// }
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/// }
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///
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/// let b1 = Book { isbn: 3, format: BookFormat::Paperback };
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/// let b2 = Book { isbn: 3, format: BookFormat::Ebook };
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/// let b3 = Book { isbn: 10, format: BookFormat::Paperback };
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///
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/// assert!(b1 == b2);
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/// assert!(b1 != b3);
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/// ```
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///
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/// ## How can I compare two different types?
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///
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/// The type you can compare with is controlled by `PartialEq`'s type parameter.
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/// For example, let's tweak our previous code a bit:
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///
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/// ```
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/// // The derive implements <BookFormat> == <BookFormat> comparisons
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/// #[derive(PartialEq)]
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/// enum BookFormat {
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/// Paperback,
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/// Hardback,
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/// Ebook,
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/// }
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///
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/// struct Book {
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/// isbn: i32,
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/// format: BookFormat,
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/// }
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///
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/// // Implement <Book> == <BookFormat> comparisons
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/// impl PartialEq<BookFormat> for Book {
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/// fn eq(&self, other: &BookFormat) -> bool {
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/// self.format == *other
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/// }
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/// }
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///
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/// // Implement <BookFormat> == <Book> comparisons
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/// impl PartialEq<Book> for BookFormat {
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/// fn eq(&self, other: &Book) -> bool {
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/// *self == other.format
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/// }
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/// }
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///
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/// let b1 = Book { isbn: 3, format: BookFormat::Paperback };
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///
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/// assert!(b1 == BookFormat::Paperback);
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/// assert!(BookFormat::Ebook != b1);
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/// ```
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///
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/// By changing `impl PartialEq for Book` to `impl PartialEq<BookFormat> for Book`,
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/// we allow `BookFormat`s to be compared with `Book`s.
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///
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/// A comparison like the one above, which ignores some fields of the struct,
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/// can be dangerous. It can easily lead to an unintended violation of the
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/// requirements for a partial equivalence relation. For example, if we kept
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/// the above implementation of `PartialEq<Book>` for `BookFormat` and added an
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/// implementation of `PartialEq<Book>` for `Book` (either via a `#[derive]` or
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/// via the manual implementation from the first example) then the result would
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/// violate transitivity:
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///
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/// ```should_panic
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/// #[derive(PartialEq)]
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/// enum BookFormat {
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/// Paperback,
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/// Hardback,
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/// Ebook,
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/// }
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///
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/// #[derive(PartialEq)]
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/// struct Book {
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/// isbn: i32,
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/// format: BookFormat,
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/// }
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///
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/// impl PartialEq<BookFormat> for Book {
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/// fn eq(&self, other: &BookFormat) -> bool {
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/// self.format == *other
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/// }
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/// }
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///
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/// impl PartialEq<Book> for BookFormat {
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/// fn eq(&self, other: &Book) -> bool {
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/// *self == other.format
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/// }
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/// }
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///
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/// fn main() {
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/// let b1 = Book { isbn: 1, format: BookFormat::Paperback };
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/// let b2 = Book { isbn: 2, format: BookFormat::Paperback };
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///
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/// assert!(b1 == BookFormat::Paperback);
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/// assert!(BookFormat::Paperback == b2);
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///
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/// // The following should hold by transitivity but doesn't.
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/// assert!(b1 == b2); // <-- PANICS
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/// }
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/// ```
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///
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/// # Examples
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///
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/// ```
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/// let x: u32 = 0;
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/// let y: u32 = 1;
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///
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/// assert_eq!(x == y, false);
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/// assert_eq!(x.eq(&y), false);
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/// ```
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///
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/// [`eq`]: PartialEq::eq
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/// [`ne`]: PartialEq::ne
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#[lang = "eq"]
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#[stable(feature = "rust1", since = "1.0.0")]
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#[doc(alias = "==")]
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#[doc(alias = "!=")]
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#[rustc_on_unimplemented(
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message = "can't compare `{Self}` with `{Rhs}`",
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label = "no implementation for `{Self} == {Rhs}`"
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)]
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pub trait PartialEq<Rhs: ?Sized = Self> {
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/// This method tests for `self` and `other` values to be equal, and is used
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/// by `==`.
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#[must_use]
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#[stable(feature = "rust1", since = "1.0.0")]
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fn eq(&self, other: &Rhs) -> bool;
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/// This method tests for `!=`.
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#[inline]
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#[must_use]
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#[stable(feature = "rust1", since = "1.0.0")]
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fn ne(&self, other: &Rhs) -> bool {
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!self.eq(other)
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}
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}
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/// Derive macro generating an impl of the trait `PartialEq`.
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#[rustc_builtin_macro]
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#[stable(feature = "builtin_macro_prelude", since = "1.38.0")]
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#[allow_internal_unstable(core_intrinsics, structural_match)]
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pub macro PartialEq($item:item) {
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/* compiler built-in */
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}
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/// Trait for equality comparisons which are [equivalence relations](
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/// https://en.wikipedia.org/wiki/Equivalence_relation).
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///
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/// This means, that in addition to `a == b` and `a != b` being strict inverses, the equality must
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/// be (for all `a`, `b` and `c`):
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///
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/// - reflexive: `a == a`;
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/// - symmetric: `a == b` implies `b == a`; and
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/// - transitive: `a == b` and `b == c` implies `a == c`.
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///
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/// This property cannot be checked by the compiler, and therefore `Eq` implies
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/// [`PartialEq`], and has no extra methods.
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///
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/// ## Derivable
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///
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/// This trait can be used with `#[derive]`. When `derive`d, because `Eq` has
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/// no extra methods, it is only informing the compiler that this is an
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/// equivalence relation rather than a partial equivalence relation. Note that
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/// the `derive` strategy requires all fields are `Eq`, which isn't
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/// always desired.
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///
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/// ## How can I implement `Eq`?
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///
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/// If you cannot use the `derive` strategy, specify that your type implements
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/// `Eq`, which has no methods:
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///
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/// ```
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/// enum BookFormat { Paperback, Hardback, Ebook }
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/// struct Book {
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/// isbn: i32,
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/// format: BookFormat,
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/// }
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/// impl PartialEq for Book {
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/// fn eq(&self, other: &Self) -> bool {
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/// self.isbn == other.isbn
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/// }
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/// }
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/// impl Eq for Book {}
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/// ```
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#[doc(alias = "==")]
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#[doc(alias = "!=")]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub trait Eq: PartialEq<Self> {
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// this method is used solely by #[deriving] to assert
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// that every component of a type implements #[deriving]
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// itself, the current deriving infrastructure means doing this
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// assertion without using a method on this trait is nearly
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// impossible.
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//
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// This should never be implemented by hand.
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#[doc(hidden)]
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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fn assert_receiver_is_total_eq(&self) {}
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}
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/// Derive macro generating an impl of the trait `Eq`.
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#[rustc_builtin_macro]
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#[stable(feature = "builtin_macro_prelude", since = "1.38.0")]
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#[allow_internal_unstable(core_intrinsics, derive_eq, structural_match)]
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pub macro Eq($item:item) {
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/* compiler built-in */
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}
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// FIXME: this struct is used solely by #[derive] to
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// assert that every component of a type implements Eq.
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//
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// This struct should never appear in user code.
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#[doc(hidden)]
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#[allow(missing_debug_implementations)]
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#[unstable(feature = "derive_eq", reason = "deriving hack, should not be public", issue = "none")]
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pub struct AssertParamIsEq<T: Eq + ?Sized> {
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_field: crate::marker::PhantomData<T>,
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}
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/// An `Ordering` is the result of a comparison between two values.
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///
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/// # Examples
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///
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/// ```
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/// use std::cmp::Ordering;
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///
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/// let result = 1.cmp(&2);
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/// assert_eq!(Ordering::Less, result);
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///
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/// let result = 1.cmp(&1);
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/// assert_eq!(Ordering::Equal, result);
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///
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/// let result = 2.cmp(&1);
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/// assert_eq!(Ordering::Greater, result);
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/// ```
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#[derive(Clone, Copy, PartialEq, Debug, Hash)]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub enum Ordering {
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/// An ordering where a compared value is less than another.
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#[stable(feature = "rust1", since = "1.0.0")]
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Less = -1,
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/// An ordering where a compared value is equal to another.
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#[stable(feature = "rust1", since = "1.0.0")]
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Equal = 0,
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/// An ordering where a compared value is greater than another.
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#[stable(feature = "rust1", since = "1.0.0")]
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Greater = 1,
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}
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impl Ordering {
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/// Reverses the `Ordering`.
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///
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/// * `Less` becomes `Greater`.
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/// * `Greater` becomes `Less`.
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/// * `Equal` becomes `Equal`.
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///
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/// # Examples
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///
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/// Basic behavior:
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///
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/// ```
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/// use std::cmp::Ordering;
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///
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/// assert_eq!(Ordering::Less.reverse(), Ordering::Greater);
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/// assert_eq!(Ordering::Equal.reverse(), Ordering::Equal);
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/// assert_eq!(Ordering::Greater.reverse(), Ordering::Less);
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/// ```
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///
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/// This method can be used to reverse a comparison:
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///
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/// ```
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/// let data: &mut [_] = &mut [2, 10, 5, 8];
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///
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/// // sort the array from largest to smallest.
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/// data.sort_by(|a, b| a.cmp(b).reverse());
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///
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/// let b: &mut [_] = &mut [10, 8, 5, 2];
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/// assert!(data == b);
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/// ```
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#[inline]
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#[must_use]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn reverse(self) -> Ordering {
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match self {
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Less => Greater,
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Equal => Equal,
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Greater => Less,
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}
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}
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/// Chains two orderings.
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///
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/// Returns `self` when it's not `Equal`. Otherwise returns `other`.
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///
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/// # Examples
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///
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/// ```
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/// use std::cmp::Ordering;
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///
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/// let result = Ordering::Equal.then(Ordering::Less);
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/// assert_eq!(result, Ordering::Less);
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///
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/// let result = Ordering::Less.then(Ordering::Equal);
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/// assert_eq!(result, Ordering::Less);
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///
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/// let result = Ordering::Less.then(Ordering::Greater);
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/// assert_eq!(result, Ordering::Less);
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///
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/// let result = Ordering::Equal.then(Ordering::Equal);
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/// assert_eq!(result, Ordering::Equal);
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///
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/// let x: (i64, i64, i64) = (1, 2, 7);
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/// let y: (i64, i64, i64) = (1, 5, 3);
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/// let result = x.0.cmp(&y.0).then(x.1.cmp(&y.1)).then(x.2.cmp(&y.2));
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///
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/// assert_eq!(result, Ordering::Less);
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/// ```
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#[inline]
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#[must_use]
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#[stable(feature = "ordering_chaining", since = "1.17.0")]
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pub fn then(self, other: Ordering) -> Ordering {
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match self {
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Equal => other,
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_ => self,
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}
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}
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/// Chains the ordering with the given function.
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///
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/// Returns `self` when it's not `Equal`. Otherwise calls `f` and returns
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/// the result.
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///
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/// # Examples
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///
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/// ```
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/// use std::cmp::Ordering;
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///
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/// let result = Ordering::Equal.then_with(|| Ordering::Less);
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/// assert_eq!(result, Ordering::Less);
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///
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/// let result = Ordering::Less.then_with(|| Ordering::Equal);
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/// assert_eq!(result, Ordering::Less);
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///
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/// let result = Ordering::Less.then_with(|| Ordering::Greater);
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/// assert_eq!(result, Ordering::Less);
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///
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/// let result = Ordering::Equal.then_with(|| Ordering::Equal);
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/// assert_eq!(result, Ordering::Equal);
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///
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/// let x: (i64, i64, i64) = (1, 2, 7);
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/// let y: (i64, i64, i64) = (1, 5, 3);
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/// let result = x.0.cmp(&y.0).then_with(|| x.1.cmp(&y.1)).then_with(|| x.2.cmp(&y.2));
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///
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/// assert_eq!(result, Ordering::Less);
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/// ```
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#[inline]
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#[must_use]
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#[stable(feature = "ordering_chaining", since = "1.17.0")]
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pub fn then_with<F: FnOnce() -> Ordering>(self, f: F) -> Ordering {
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match self {
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Equal => f(),
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_ => self,
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}
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}
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}
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/// A helper struct for reverse ordering.
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///
|
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/// This struct is a helper to be used with functions like [`Vec::sort_by_key`] and
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/// can be used to reverse order a part of a key.
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///
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|
/// [`Vec::sort_by_key`]: ../../std/vec/struct.Vec.html#method.sort_by_key
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///
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/// # Examples
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|
///
|
|
/// ```
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/// use std::cmp::Reverse;
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///
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/// let mut v = vec![1, 2, 3, 4, 5, 6];
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/// v.sort_by_key(|&num| (num > 3, Reverse(num)));
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/// assert_eq!(v, vec![3, 2, 1, 6, 5, 4]);
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/// ```
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#[derive(PartialEq, Eq, Debug, Copy, Clone, Default, Hash)]
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#[stable(feature = "reverse_cmp_key", since = "1.19.0")]
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pub struct Reverse<T>(#[stable(feature = "reverse_cmp_key", since = "1.19.0")] pub T);
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#[stable(feature = "reverse_cmp_key", since = "1.19.0")]
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impl<T: PartialOrd> PartialOrd for Reverse<T> {
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#[inline]
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fn partial_cmp(&self, other: &Reverse<T>) -> Option<Ordering> {
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other.0.partial_cmp(&self.0)
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}
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#[inline]
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fn lt(&self, other: &Self) -> bool {
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other.0 < self.0
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}
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#[inline]
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fn le(&self, other: &Self) -> bool {
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other.0 <= self.0
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}
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#[inline]
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fn gt(&self, other: &Self) -> bool {
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other.0 > self.0
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}
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#[inline]
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|
fn ge(&self, other: &Self) -> bool {
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other.0 >= self.0
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}
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}
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#[stable(feature = "reverse_cmp_key", since = "1.19.0")]
|
|
impl<T: Ord> Ord for Reverse<T> {
|
|
#[inline]
|
|
fn cmp(&self, other: &Reverse<T>) -> Ordering {
|
|
other.0.cmp(&self.0)
|
|
}
|
|
}
|
|
|
|
/// Trait for types that form a [total order](https://en.wikipedia.org/wiki/Total_order).
|
|
///
|
|
/// An order is a total order if it is (for all `a`, `b` and `c`):
|
|
///
|
|
/// - total and asymmetric: exactly one of `a < b`, `a == b` or `a > b` is true; and
|
|
/// - transitive, `a < b` and `b < c` implies `a < c`. The same must hold for both `==` and `>`.
|
|
///
|
|
/// ## Derivable
|
|
///
|
|
/// This trait can be used with `#[derive]`. When `derive`d on structs, it will produce a
|
|
/// lexicographic ordering based on the top-to-bottom declaration order of the struct's members.
|
|
/// When `derive`d on enums, variants are ordered by their top-to-bottom discriminant order.
|
|
///
|
|
/// ## How can I implement `Ord`?
|
|
///
|
|
/// `Ord` requires that the type also be [`PartialOrd`] and [`Eq`] (which requires [`PartialEq`]).
|
|
///
|
|
/// Then you must define an implementation for [`cmp`]. You may find it useful to use
|
|
/// [`cmp`] on your type's fields.
|
|
///
|
|
/// Implementations of [`PartialEq`], [`PartialOrd`], and `Ord` *must*
|
|
/// agree with each other. That is, `a.cmp(b) == Ordering::Equal` if
|
|
/// and only if `a == b` and `Some(a.cmp(b)) == a.partial_cmp(b)` for
|
|
/// all `a` and `b`. It's easy to accidentally make them disagree by
|
|
/// deriving some of the traits and manually implementing others.
|
|
///
|
|
/// Here's an example where you want to sort people by height only, disregarding `id`
|
|
/// and `name`:
|
|
///
|
|
/// ```
|
|
/// use std::cmp::Ordering;
|
|
///
|
|
/// #[derive(Eq)]
|
|
/// struct Person {
|
|
/// id: u32,
|
|
/// name: String,
|
|
/// height: u32,
|
|
/// }
|
|
///
|
|
/// impl Ord for Person {
|
|
/// fn cmp(&self, other: &Self) -> Ordering {
|
|
/// self.height.cmp(&other.height)
|
|
/// }
|
|
/// }
|
|
///
|
|
/// impl PartialOrd for Person {
|
|
/// fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
|
|
/// Some(self.cmp(other))
|
|
/// }
|
|
/// }
|
|
///
|
|
/// impl PartialEq for Person {
|
|
/// fn eq(&self, other: &Self) -> bool {
|
|
/// self.height == other.height
|
|
/// }
|
|
/// }
|
|
/// ```
|
|
///
|
|
/// [`cmp`]: Ord::cmp
|
|
#[doc(alias = "<")]
|
|
#[doc(alias = ">")]
|
|
#[doc(alias = "<=")]
|
|
#[doc(alias = ">=")]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub trait Ord: Eq + PartialOrd<Self> {
|
|
/// This method returns an [`Ordering`] between `self` and `other`.
|
|
///
|
|
/// By convention, `self.cmp(&other)` returns the ordering matching the expression
|
|
/// `self <operator> other` if true.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::cmp::Ordering;
|
|
///
|
|
/// assert_eq!(5.cmp(&10), Ordering::Less);
|
|
/// assert_eq!(10.cmp(&5), Ordering::Greater);
|
|
/// assert_eq!(5.cmp(&5), Ordering::Equal);
|
|
/// ```
|
|
#[must_use]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
fn cmp(&self, other: &Self) -> Ordering;
|
|
|
|
/// Compares and returns the maximum of two values.
|
|
///
|
|
/// Returns the second argument if the comparison determines them to be equal.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// assert_eq!(2, 1.max(2));
|
|
/// assert_eq!(2, 2.max(2));
|
|
/// ```
|
|
#[stable(feature = "ord_max_min", since = "1.21.0")]
|
|
#[inline]
|
|
#[must_use]
|
|
fn max(self, other: Self) -> Self
|
|
where
|
|
Self: Sized,
|
|
{
|
|
max_by(self, other, Ord::cmp)
|
|
}
|
|
|
|
/// Compares and returns the minimum of two values.
|
|
///
|
|
/// Returns the first argument if the comparison determines them to be equal.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// assert_eq!(1, 1.min(2));
|
|
/// assert_eq!(2, 2.min(2));
|
|
/// ```
|
|
#[stable(feature = "ord_max_min", since = "1.21.0")]
|
|
#[inline]
|
|
#[must_use]
|
|
fn min(self, other: Self) -> Self
|
|
where
|
|
Self: Sized,
|
|
{
|
|
min_by(self, other, Ord::cmp)
|
|
}
|
|
|
|
/// Restrict a value to a certain interval.
|
|
///
|
|
/// Returns `max` if `self` is greater than `max`, and `min` if `self` is
|
|
/// less than `min`. Otherwise this returns `self`.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// Panics if `min > max`.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// #![feature(clamp)]
|
|
///
|
|
/// assert!((-3).clamp(-2, 1) == -2);
|
|
/// assert!(0.clamp(-2, 1) == 0);
|
|
/// assert!(2.clamp(-2, 1) == 1);
|
|
/// ```
|
|
#[must_use]
|
|
#[unstable(feature = "clamp", issue = "44095")]
|
|
fn clamp(self, min: Self, max: Self) -> Self
|
|
where
|
|
Self: Sized,
|
|
{
|
|
assert!(min <= max);
|
|
if self < min {
|
|
min
|
|
} else if self > max {
|
|
max
|
|
} else {
|
|
self
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Derive macro generating an impl of the trait `Ord`.
|
|
#[rustc_builtin_macro]
|
|
#[stable(feature = "builtin_macro_prelude", since = "1.38.0")]
|
|
#[allow_internal_unstable(core_intrinsics)]
|
|
pub macro Ord($item:item) {
|
|
/* compiler built-in */
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl Eq for Ordering {}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl Ord for Ordering {
|
|
#[inline]
|
|
fn cmp(&self, other: &Ordering) -> Ordering {
|
|
(*self as i32).cmp(&(*other as i32))
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl PartialOrd for Ordering {
|
|
#[inline]
|
|
fn partial_cmp(&self, other: &Ordering) -> Option<Ordering> {
|
|
(*self as i32).partial_cmp(&(*other as i32))
|
|
}
|
|
}
|
|
|
|
/// Trait for values that can be compared for a sort-order.
|
|
///
|
|
/// The comparison must satisfy, for all `a`, `b` and `c`:
|
|
///
|
|
/// - asymmetry: if `a < b` then `!(a > b)`, as well as `a > b` implying `!(a < b)`; and
|
|
/// - transitivity: `a < b` and `b < c` implies `a < c`. The same must hold for both `==` and `>`.
|
|
///
|
|
/// Note that these requirements mean that the trait itself must be implemented symmetrically and
|
|
/// transitively: if `T: PartialOrd<U>` and `U: PartialOrd<V>` then `U: PartialOrd<T>` and `T:
|
|
/// PartialOrd<V>`.
|
|
///
|
|
/// ## Derivable
|
|
///
|
|
/// This trait can be used with `#[derive]`. When `derive`d on structs, it will produce a
|
|
/// lexicographic ordering based on the top-to-bottom declaration order of the struct's members.
|
|
/// When `derive`d on enums, variants are ordered by their top-to-bottom discriminant order.
|
|
///
|
|
/// ## How can I implement `PartialOrd`?
|
|
///
|
|
/// `PartialOrd` only requires implementation of the [`partial_cmp`] method, with the others
|
|
/// generated from default implementations.
|
|
///
|
|
/// However it remains possible to implement the others separately for types which do not have a
|
|
/// total order. For example, for floating point numbers, `NaN < 0 == false` and `NaN >= 0 ==
|
|
/// false` (cf. IEEE 754-2008 section 5.11).
|
|
///
|
|
/// `PartialOrd` requires your type to be [`PartialEq`].
|
|
///
|
|
/// Implementations of [`PartialEq`], `PartialOrd`, and [`Ord`] *must* agree with each other. It's
|
|
/// easy to accidentally make them disagree by deriving some of the traits and manually
|
|
/// implementing others.
|
|
///
|
|
/// If your type is [`Ord`], you can implement [`partial_cmp`] by using [`cmp`]:
|
|
///
|
|
/// ```
|
|
/// use std::cmp::Ordering;
|
|
///
|
|
/// #[derive(Eq)]
|
|
/// struct Person {
|
|
/// id: u32,
|
|
/// name: String,
|
|
/// height: u32,
|
|
/// }
|
|
///
|
|
/// impl PartialOrd for Person {
|
|
/// fn partial_cmp(&self, other: &Person) -> Option<Ordering> {
|
|
/// Some(self.cmp(other))
|
|
/// }
|
|
/// }
|
|
///
|
|
/// impl Ord for Person {
|
|
/// fn cmp(&self, other: &Person) -> Ordering {
|
|
/// self.height.cmp(&other.height)
|
|
/// }
|
|
/// }
|
|
///
|
|
/// impl PartialEq for Person {
|
|
/// fn eq(&self, other: &Person) -> bool {
|
|
/// self.height == other.height
|
|
/// }
|
|
/// }
|
|
/// ```
|
|
///
|
|
/// You may also find it useful to use [`partial_cmp`] on your type's fields. Here
|
|
/// is an example of `Person` types who have a floating-point `height` field that
|
|
/// is the only field to be used for sorting:
|
|
///
|
|
/// ```
|
|
/// use std::cmp::Ordering;
|
|
///
|
|
/// struct Person {
|
|
/// id: u32,
|
|
/// name: String,
|
|
/// height: f64,
|
|
/// }
|
|
///
|
|
/// impl PartialOrd for Person {
|
|
/// fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
|
|
/// self.height.partial_cmp(&other.height)
|
|
/// }
|
|
/// }
|
|
///
|
|
/// impl PartialEq for Person {
|
|
/// fn eq(&self, other: &Self) -> bool {
|
|
/// self.height == other.height
|
|
/// }
|
|
/// }
|
|
/// ```
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// let x : u32 = 0;
|
|
/// let y : u32 = 1;
|
|
///
|
|
/// assert_eq!(x < y, true);
|
|
/// assert_eq!(x.lt(&y), true);
|
|
/// ```
|
|
///
|
|
/// [`partial_cmp`]: PartialOrd::partial_cmp
|
|
/// [`cmp`]: Ord::cmp
|
|
#[lang = "partial_ord"]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[doc(alias = ">")]
|
|
#[doc(alias = "<")]
|
|
#[doc(alias = "<=")]
|
|
#[doc(alias = ">=")]
|
|
#[rustc_on_unimplemented(
|
|
message = "can't compare `{Self}` with `{Rhs}`",
|
|
label = "no implementation for `{Self} < {Rhs}` and `{Self} > {Rhs}`"
|
|
)]
|
|
pub trait PartialOrd<Rhs: ?Sized = Self>: PartialEq<Rhs> {
|
|
/// This method returns an ordering between `self` and `other` values if one exists.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::cmp::Ordering;
|
|
///
|
|
/// let result = 1.0.partial_cmp(&2.0);
|
|
/// assert_eq!(result, Some(Ordering::Less));
|
|
///
|
|
/// let result = 1.0.partial_cmp(&1.0);
|
|
/// assert_eq!(result, Some(Ordering::Equal));
|
|
///
|
|
/// let result = 2.0.partial_cmp(&1.0);
|
|
/// assert_eq!(result, Some(Ordering::Greater));
|
|
/// ```
|
|
///
|
|
/// When comparison is impossible:
|
|
///
|
|
/// ```
|
|
/// let result = f64::NAN.partial_cmp(&1.0);
|
|
/// assert_eq!(result, None);
|
|
/// ```
|
|
#[must_use]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
fn partial_cmp(&self, other: &Rhs) -> Option<Ordering>;
|
|
|
|
/// This method tests less than (for `self` and `other`) and is used by the `<` operator.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// let result = 1.0 < 2.0;
|
|
/// assert_eq!(result, true);
|
|
///
|
|
/// let result = 2.0 < 1.0;
|
|
/// assert_eq!(result, false);
|
|
/// ```
|
|
#[inline]
|
|
#[must_use]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
fn lt(&self, other: &Rhs) -> bool {
|
|
matches!(self.partial_cmp(other), Some(Less))
|
|
}
|
|
|
|
/// This method tests less than or equal to (for `self` and `other`) and is used by the `<=`
|
|
/// operator.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// let result = 1.0 <= 2.0;
|
|
/// assert_eq!(result, true);
|
|
///
|
|
/// let result = 2.0 <= 2.0;
|
|
/// assert_eq!(result, true);
|
|
/// ```
|
|
#[inline]
|
|
#[must_use]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
fn le(&self, other: &Rhs) -> bool {
|
|
matches!(self.partial_cmp(other), Some(Less | Equal))
|
|
}
|
|
|
|
/// This method tests greater than (for `self` and `other`) and is used by the `>` operator.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// let result = 1.0 > 2.0;
|
|
/// assert_eq!(result, false);
|
|
///
|
|
/// let result = 2.0 > 2.0;
|
|
/// assert_eq!(result, false);
|
|
/// ```
|
|
#[inline]
|
|
#[must_use]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
fn gt(&self, other: &Rhs) -> bool {
|
|
matches!(self.partial_cmp(other), Some(Greater))
|
|
}
|
|
|
|
/// This method tests greater than or equal to (for `self` and `other`) and is used by the `>=`
|
|
/// operator.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// let result = 2.0 >= 1.0;
|
|
/// assert_eq!(result, true);
|
|
///
|
|
/// let result = 2.0 >= 2.0;
|
|
/// assert_eq!(result, true);
|
|
/// ```
|
|
#[inline]
|
|
#[must_use]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
fn ge(&self, other: &Rhs) -> bool {
|
|
matches!(self.partial_cmp(other), Some(Greater | Equal))
|
|
}
|
|
}
|
|
|
|
/// Derive macro generating an impl of the trait `PartialOrd`.
|
|
#[rustc_builtin_macro]
|
|
#[stable(feature = "builtin_macro_prelude", since = "1.38.0")]
|
|
#[allow_internal_unstable(core_intrinsics)]
|
|
pub macro PartialOrd($item:item) {
|
|
/* compiler built-in */
|
|
}
|
|
|
|
/// Compares and returns the minimum of two values.
|
|
///
|
|
/// Returns the first argument if the comparison determines them to be equal.
|
|
///
|
|
/// Internally uses an alias to [`Ord::min`].
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::cmp;
|
|
///
|
|
/// assert_eq!(1, cmp::min(1, 2));
|
|
/// assert_eq!(2, cmp::min(2, 2));
|
|
/// ```
|
|
#[inline]
|
|
#[must_use]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn min<T: Ord>(v1: T, v2: T) -> T {
|
|
v1.min(v2)
|
|
}
|
|
|
|
/// Returns the minimum of two values with respect to the specified comparison function.
|
|
///
|
|
/// Returns the first argument if the comparison determines them to be equal.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// #![feature(cmp_min_max_by)]
|
|
///
|
|
/// use std::cmp;
|
|
///
|
|
/// assert_eq!(cmp::min_by(-2, 1, |x: &i32, y: &i32| x.abs().cmp(&y.abs())), 1);
|
|
/// assert_eq!(cmp::min_by(-2, 2, |x: &i32, y: &i32| x.abs().cmp(&y.abs())), -2);
|
|
/// ```
|
|
#[inline]
|
|
#[must_use]
|
|
#[unstable(feature = "cmp_min_max_by", issue = "64460")]
|
|
pub fn min_by<T, F: FnOnce(&T, &T) -> Ordering>(v1: T, v2: T, compare: F) -> T {
|
|
match compare(&v1, &v2) {
|
|
Ordering::Less | Ordering::Equal => v1,
|
|
Ordering::Greater => v2,
|
|
}
|
|
}
|
|
|
|
/// Returns the element that gives the minimum value from the specified function.
|
|
///
|
|
/// Returns the first argument if the comparison determines them to be equal.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// #![feature(cmp_min_max_by)]
|
|
///
|
|
/// use std::cmp;
|
|
///
|
|
/// assert_eq!(cmp::min_by_key(-2, 1, |x: &i32| x.abs()), 1);
|
|
/// assert_eq!(cmp::min_by_key(-2, 2, |x: &i32| x.abs()), -2);
|
|
/// ```
|
|
#[inline]
|
|
#[must_use]
|
|
#[unstable(feature = "cmp_min_max_by", issue = "64460")]
|
|
pub fn min_by_key<T, F: FnMut(&T) -> K, K: Ord>(v1: T, v2: T, mut f: F) -> T {
|
|
min_by(v1, v2, |v1, v2| f(v1).cmp(&f(v2)))
|
|
}
|
|
|
|
/// Compares and returns the maximum of two values.
|
|
///
|
|
/// Returns the second argument if the comparison determines them to be equal.
|
|
///
|
|
/// Internally uses an alias to [`Ord::max`].
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::cmp;
|
|
///
|
|
/// assert_eq!(2, cmp::max(1, 2));
|
|
/// assert_eq!(2, cmp::max(2, 2));
|
|
/// ```
|
|
#[inline]
|
|
#[must_use]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn max<T: Ord>(v1: T, v2: T) -> T {
|
|
v1.max(v2)
|
|
}
|
|
|
|
/// Returns the maximum of two values with respect to the specified comparison function.
|
|
///
|
|
/// Returns the second argument if the comparison determines them to be equal.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// #![feature(cmp_min_max_by)]
|
|
///
|
|
/// use std::cmp;
|
|
///
|
|
/// assert_eq!(cmp::max_by(-2, 1, |x: &i32, y: &i32| x.abs().cmp(&y.abs())), -2);
|
|
/// assert_eq!(cmp::max_by(-2, 2, |x: &i32, y: &i32| x.abs().cmp(&y.abs())), 2);
|
|
/// ```
|
|
#[inline]
|
|
#[must_use]
|
|
#[unstable(feature = "cmp_min_max_by", issue = "64460")]
|
|
pub fn max_by<T, F: FnOnce(&T, &T) -> Ordering>(v1: T, v2: T, compare: F) -> T {
|
|
match compare(&v1, &v2) {
|
|
Ordering::Less | Ordering::Equal => v2,
|
|
Ordering::Greater => v1,
|
|
}
|
|
}
|
|
|
|
/// Returns the element that gives the maximum value from the specified function.
|
|
///
|
|
/// Returns the second argument if the comparison determines them to be equal.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// #![feature(cmp_min_max_by)]
|
|
///
|
|
/// use std::cmp;
|
|
///
|
|
/// assert_eq!(cmp::max_by_key(-2, 1, |x: &i32| x.abs()), -2);
|
|
/// assert_eq!(cmp::max_by_key(-2, 2, |x: &i32| x.abs()), 2);
|
|
/// ```
|
|
#[inline]
|
|
#[must_use]
|
|
#[unstable(feature = "cmp_min_max_by", issue = "64460")]
|
|
pub fn max_by_key<T, F: FnMut(&T) -> K, K: Ord>(v1: T, v2: T, mut f: F) -> T {
|
|
max_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};
|
|
use crate::hint::unreachable_unchecked;
|
|
|
|
macro_rules! partial_eq_impl {
|
|
($($t:ty)*) => ($(
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl PartialEq for $t {
|
|
#[inline]
|
|
fn eq(&self, other: &$t) -> bool { (*self) == (*other) }
|
|
#[inline]
|
|
fn ne(&self, other: &$t) -> bool { (*self) != (*other) }
|
|
}
|
|
)*)
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl PartialEq for () {
|
|
#[inline]
|
|
fn eq(&self, _other: &()) -> bool {
|
|
true
|
|
}
|
|
#[inline]
|
|
fn ne(&self, _other: &()) -> bool {
|
|
false
|
|
}
|
|
}
|
|
|
|
partial_eq_impl! {
|
|
bool char usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64
|
|
}
|
|
|
|
macro_rules! eq_impl {
|
|
($($t:ty)*) => ($(
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl Eq for $t {}
|
|
)*)
|
|
}
|
|
|
|
eq_impl! { () bool char usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }
|
|
|
|
macro_rules! partial_ord_impl {
|
|
($($t:ty)*) => ($(
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl PartialOrd for $t {
|
|
#[inline]
|
|
fn partial_cmp(&self, other: &$t) -> Option<Ordering> {
|
|
match (self <= other, self >= other) {
|
|
(false, false) => None,
|
|
(false, true) => Some(Greater),
|
|
(true, false) => Some(Less),
|
|
(true, true) => Some(Equal),
|
|
}
|
|
}
|
|
#[inline]
|
|
fn lt(&self, other: &$t) -> bool { (*self) < (*other) }
|
|
#[inline]
|
|
fn le(&self, other: &$t) -> bool { (*self) <= (*other) }
|
|
#[inline]
|
|
fn ge(&self, other: &$t) -> bool { (*self) >= (*other) }
|
|
#[inline]
|
|
fn gt(&self, other: &$t) -> bool { (*self) > (*other) }
|
|
}
|
|
)*)
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl PartialOrd for () {
|
|
#[inline]
|
|
fn partial_cmp(&self, _: &()) -> Option<Ordering> {
|
|
Some(Equal)
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl PartialOrd for bool {
|
|
#[inline]
|
|
fn partial_cmp(&self, other: &bool) -> Option<Ordering> {
|
|
(*self as u8).partial_cmp(&(*other as u8))
|
|
}
|
|
}
|
|
|
|
partial_ord_impl! { f32 f64 }
|
|
|
|
macro_rules! ord_impl {
|
|
($($t:ty)*) => ($(
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl PartialOrd for $t {
|
|
#[inline]
|
|
fn partial_cmp(&self, other: &$t) -> Option<Ordering> {
|
|
Some(self.cmp(other))
|
|
}
|
|
#[inline]
|
|
fn lt(&self, other: &$t) -> bool { (*self) < (*other) }
|
|
#[inline]
|
|
fn le(&self, other: &$t) -> bool { (*self) <= (*other) }
|
|
#[inline]
|
|
fn ge(&self, other: &$t) -> bool { (*self) >= (*other) }
|
|
#[inline]
|
|
fn gt(&self, other: &$t) -> bool { (*self) > (*other) }
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl Ord for $t {
|
|
#[inline]
|
|
fn cmp(&self, other: &$t) -> Ordering {
|
|
// The order here is important to generate more optimal assembly.
|
|
// See <https://github.com/rust-lang/rust/issues/63758> for more info.
|
|
if *self < *other { Less }
|
|
else if *self == *other { Equal }
|
|
else { Greater }
|
|
}
|
|
}
|
|
)*)
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl Ord for () {
|
|
#[inline]
|
|
fn cmp(&self, _other: &()) -> Ordering {
|
|
Equal
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl Ord for bool {
|
|
#[inline]
|
|
fn cmp(&self, other: &bool) -> Ordering {
|
|
// Casting to i8's and converting the difference to an Ordering generates
|
|
// more optimal assembly.
|
|
// See <https://github.com/rust-lang/rust/issues/66780> for more info.
|
|
match (*self as i8) - (*other as i8) {
|
|
-1 => Less,
|
|
0 => Equal,
|
|
1 => Greater,
|
|
// SAFETY: bool as i8 returns 0 or 1, so the difference can't be anything else
|
|
_ => unsafe { unreachable_unchecked() },
|
|
}
|
|
}
|
|
}
|
|
|
|
ord_impl! { char usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }
|
|
|
|
#[unstable(feature = "never_type", issue = "35121")]
|
|
impl PartialEq for ! {
|
|
fn eq(&self, _: &!) -> bool {
|
|
*self
|
|
}
|
|
}
|
|
|
|
#[unstable(feature = "never_type", issue = "35121")]
|
|
impl Eq for ! {}
|
|
|
|
#[unstable(feature = "never_type", issue = "35121")]
|
|
impl PartialOrd for ! {
|
|
fn partial_cmp(&self, _: &!) -> Option<Ordering> {
|
|
*self
|
|
}
|
|
}
|
|
|
|
#[unstable(feature = "never_type", issue = "35121")]
|
|
impl Ord for ! {
|
|
fn cmp(&self, _: &!) -> Ordering {
|
|
*self
|
|
}
|
|
}
|
|
|
|
// & pointers
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<A: ?Sized, B: ?Sized> PartialEq<&B> for &A
|
|
where
|
|
A: PartialEq<B>,
|
|
{
|
|
#[inline]
|
|
fn eq(&self, other: &&B) -> bool {
|
|
PartialEq::eq(*self, *other)
|
|
}
|
|
#[inline]
|
|
fn ne(&self, other: &&B) -> bool {
|
|
PartialEq::ne(*self, *other)
|
|
}
|
|
}
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<A: ?Sized, B: ?Sized> PartialOrd<&B> for &A
|
|
where
|
|
A: PartialOrd<B>,
|
|
{
|
|
#[inline]
|
|
fn partial_cmp(&self, other: &&B) -> Option<Ordering> {
|
|
PartialOrd::partial_cmp(*self, *other)
|
|
}
|
|
#[inline]
|
|
fn lt(&self, other: &&B) -> bool {
|
|
PartialOrd::lt(*self, *other)
|
|
}
|
|
#[inline]
|
|
fn le(&self, other: &&B) -> bool {
|
|
PartialOrd::le(*self, *other)
|
|
}
|
|
#[inline]
|
|
fn gt(&self, other: &&B) -> bool {
|
|
PartialOrd::gt(*self, *other)
|
|
}
|
|
#[inline]
|
|
fn ge(&self, other: &&B) -> bool {
|
|
PartialOrd::ge(*self, *other)
|
|
}
|
|
}
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<A: ?Sized> Ord for &A
|
|
where
|
|
A: Ord,
|
|
{
|
|
#[inline]
|
|
fn cmp(&self, other: &Self) -> Ordering {
|
|
Ord::cmp(*self, *other)
|
|
}
|
|
}
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<A: ?Sized> Eq for &A where A: Eq {}
|
|
|
|
// &mut pointers
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<A: ?Sized, B: ?Sized> PartialEq<&mut B> for &mut A
|
|
where
|
|
A: PartialEq<B>,
|
|
{
|
|
#[inline]
|
|
fn eq(&self, other: &&mut B) -> bool {
|
|
PartialEq::eq(*self, *other)
|
|
}
|
|
#[inline]
|
|
fn ne(&self, other: &&mut B) -> bool {
|
|
PartialEq::ne(*self, *other)
|
|
}
|
|
}
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<A: ?Sized, B: ?Sized> PartialOrd<&mut B> for &mut A
|
|
where
|
|
A: PartialOrd<B>,
|
|
{
|
|
#[inline]
|
|
fn partial_cmp(&self, other: &&mut B) -> Option<Ordering> {
|
|
PartialOrd::partial_cmp(*self, *other)
|
|
}
|
|
#[inline]
|
|
fn lt(&self, other: &&mut B) -> bool {
|
|
PartialOrd::lt(*self, *other)
|
|
}
|
|
#[inline]
|
|
fn le(&self, other: &&mut B) -> bool {
|
|
PartialOrd::le(*self, *other)
|
|
}
|
|
#[inline]
|
|
fn gt(&self, other: &&mut B) -> bool {
|
|
PartialOrd::gt(*self, *other)
|
|
}
|
|
#[inline]
|
|
fn ge(&self, other: &&mut B) -> bool {
|
|
PartialOrd::ge(*self, *other)
|
|
}
|
|
}
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<A: ?Sized> Ord for &mut A
|
|
where
|
|
A: Ord,
|
|
{
|
|
#[inline]
|
|
fn cmp(&self, other: &Self) -> Ordering {
|
|
Ord::cmp(*self, *other)
|
|
}
|
|
}
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<A: ?Sized> Eq for &mut A where A: Eq {}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<A: ?Sized, B: ?Sized> PartialEq<&mut B> for &A
|
|
where
|
|
A: PartialEq<B>,
|
|
{
|
|
#[inline]
|
|
fn eq(&self, other: &&mut B) -> bool {
|
|
PartialEq::eq(*self, *other)
|
|
}
|
|
#[inline]
|
|
fn ne(&self, other: &&mut B) -> bool {
|
|
PartialEq::ne(*self, *other)
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<A: ?Sized, B: ?Sized> PartialEq<&B> for &mut A
|
|
where
|
|
A: PartialEq<B>,
|
|
{
|
|
#[inline]
|
|
fn eq(&self, other: &&B) -> bool {
|
|
PartialEq::eq(*self, *other)
|
|
}
|
|
#[inline]
|
|
fn ne(&self, other: &&B) -> bool {
|
|
PartialEq::ne(*self, *other)
|
|
}
|
|
}
|
|
}
|