1.0.0[−][src]Trait ontio_std::prelude::cmp::PartialOrd

#[lang = "partial_ord"]pub trait PartialOrd<Rhs = Self>: PartialEq<Rhs> where
    Rhs: ?Sized, {
#[must_use]    pub fn partial_cmp(&self, other: &Rhs) -> Option<Ordering>;

#[must_use]    pub fn lt(&self, other: &Rhs) -> bool { ... }
#[must_use]    pub fn le(&self, other: &Rhs) -> bool { ... }
#[must_use]    pub fn gt(&self, other: &Rhs) -> bool { ... }
#[must_use]    pub fn ge(&self, other: &Rhs) -> bool { ... }
}

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 and U: PartialOrd<V> then U: PartialOrd<T> and T: PartialOrd<V>.

Derivable

This trait can be used with #[derive]. When derived on structs, it will produce a lexicographic ordering based on the top-to-bottom declaration order of the struct's members. When derived 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: &Self) -> Option<Ordering> {
        Some(self.cmp(other))
    }
}

impl Ord for Person {
    fn cmp(&self, other: &Self) -> Ordering {
        self.height.cmp(&other.height)
    }
}

impl PartialEq for Person {
    fn eq(&self, other: &Self) -> 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);

Required methods

`#[must_use]pub fn partial_cmp(&self, other: &Rhs) -> Option<Ordering>`[src]

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);

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Provided methods

`#[must_use]pub fn lt(&self, other: &Rhs) -> bool`[src]

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);

`#[must_use]pub fn le(&self, other: &Rhs) -> bool`[src]

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);

`#[must_use]pub fn gt(&self, other: &Rhs) -> bool`[src]

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);

`#[must_use]pub fn ge(&self, other: &Rhs) -> bool`[src]

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);

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Implementations on Foreign Types

`impl PartialOrd<NonZeroU64> for NonZeroU64`[src]

`pub fn partial_cmp(&self, other: &NonZeroU64) -> Option<Ordering>`[src]

`pub fn lt(&self, other: &NonZeroU64) -> bool`[src]

`pub fn le(&self, other: &NonZeroU64) -> bool`[src]

`pub fn gt(&self, other: &NonZeroU64) -> bool`[src]

`pub fn ge(&self, other: &NonZeroU64) -> bool`[src]

`impl PartialOrd<NonZeroU8> for NonZeroU8`[src]

`pub fn partial_cmp(&self, other: &NonZeroU8) -> Option<Ordering>`[src]

`pub fn lt(&self, other: &NonZeroU8) -> bool`[src]

`pub fn le(&self, other: &NonZeroU8) -> bool`[src]

`pub fn gt(&self, other: &NonZeroU8) -> bool`[src]

`pub fn ge(&self, other: &NonZeroU8) -> bool`[src]

`impl PartialOrd<NonZeroI16> for NonZeroI16`[src]

`pub fn partial_cmp(&self, other: &NonZeroI16) -> Option<Ordering>`[src]

`pub fn lt(&self, other: &NonZeroI16) -> bool`[src]

`pub fn le(&self, other: &NonZeroI16) -> bool`[src]

`pub fn gt(&self, other: &NonZeroI16) -> bool`[src]

`pub fn ge(&self, other: &NonZeroI16) -> bool`[src]

`impl<P, Q> PartialOrd<Pin<Q>> for Pin where P: Deref, Q: Deref, ::Target: PartialOrd<<Q as Deref>::Target>,` [src]

`pub fn partial_cmp(&self, other: &Pin<Q>) -> Option<Ordering>`[src]

`pub fn lt(&self, other: &Pin<Q>) -> bool`[src]

`pub fn le(&self, other: &Pin<Q>) -> bool`[src]

`pub fn gt(&self, other: &Pin<Q>) -> bool`[src]

`pub fn ge(&self, other: &Pin<Q>) -> bool`[src]

`impl<T> PartialOrd<Poll<T>> for Poll<T> where T: PartialOrd<T>,` [src]

`pub fn partial_cmp(&self, other: &Poll<T>) -> Option<Ordering>`[src]

`pub fn lt(&self, other: &Poll<T>) -> bool`[src]

`pub fn le(&self, other: &Poll<T>) -> bool`[src]

`pub fn gt(&self, other: &Poll<T>) -> bool`[src]

`pub fn ge(&self, other: &Poll<T>) -> bool`[src]

`impl PartialOrd<NonZeroU128> for NonZeroU128`[src]

`pub fn partial_cmp(&self, other: &NonZeroU128) -> Option<Ordering>`[src]

`pub fn lt(&self, other: &NonZeroU128) -> bool`[src]

`pub fn le(&self, other: &NonZeroU128) -> bool`[src]

`pub fn gt(&self, other: &NonZeroU128) -> bool`[src]

`pub fn ge(&self, other: &NonZeroU128) -> bool`[src]

`impl<T> PartialOrd<ManuallyDrop<T>> for ManuallyDrop<T> where T: PartialOrd<T> + ?Sized,` [src]

`pub fn partial_cmp(&self, other: &ManuallyDrop<T>) -> Option<Ordering>`[src]

`pub fn lt(&self, other: &ManuallyDrop<T>) -> bool`[src]

`pub fn le(&self, other: &ManuallyDrop<T>) -> bool`[src]

`pub fn gt(&self, other: &ManuallyDrop<T>) -> bool`[src]

`pub fn ge(&self, other: &ManuallyDrop<T>) -> bool`[src]

`impl PartialOrd<Duration> for Duration`[src]

`pub fn partial_cmp(&self, other: &Duration) -> Option<Ordering>`[src]

`pub fn lt(&self, other: &Duration) -> bool`[src]

`pub fn le(&self, other: &Duration) -> bool`[src]

`pub fn gt(&self, other: &Duration) -> bool`[src]

`pub fn ge(&self, other: &Duration) -> bool`[src]

`impl PartialOrd<Infallible> for Infallible`[src]

`pub fn partial_cmp(&self, _other: &Infallible) -> Option<Ordering>`[src]

`impl PartialOrd<NonZeroI8> for NonZeroI8`[src]

`pub fn partial_cmp(&self, other: &NonZeroI8) -> Option<Ordering>`[src]

`pub fn lt(&self, other: &NonZeroI8) -> bool`[src]

`pub fn le(&self, other: &NonZeroI8) -> bool`[src]

`pub fn gt(&self, other: &NonZeroI8) -> bool`[src]

`pub fn ge(&self, other: &NonZeroI8) -> bool`[src]

`impl PartialOrd<CpuidResult> for CpuidResult`[src]

`pub fn partial_cmp(&self, other: &CpuidResult) -> Option<Ordering>`[src]

`pub fn lt(&self, other: &CpuidResult) -> bool`[src]

`pub fn le(&self, other: &CpuidResult) -> bool`[src]

`pub fn gt(&self, other: &CpuidResult) -> bool`[src]

`pub fn ge(&self, other: &CpuidResult) -> bool`[src]

`impl<Y, R> PartialOrd<GeneratorState<Y, R>> for GeneratorState<Y, R> where R: PartialOrd<R>, Y: PartialOrd<Y>,` [src]

`pub fn partial_cmp(&self, other: &GeneratorState<Y, R>) -> Option<Ordering>`[src]

`pub fn lt(&self, other: &GeneratorState<Y, R>) -> bool`[src]

`pub fn le(&self, other: &GeneratorState<Y, R>) -> bool`[src]

`pub fn gt(&self, other: &GeneratorState<Y, R>) -> bool`[src]

`pub fn ge(&self, other: &GeneratorState<Y, R>) -> bool`[src]

`impl PartialOrd<NonZeroU16> for NonZeroU16`[src]

`pub fn partial_cmp(&self, other: &NonZeroU16) -> Option<Ordering>`[src]

`pub fn lt(&self, other: &NonZeroU16) -> bool`[src]

`pub fn le(&self, other: &NonZeroU16) -> bool`[src]

`pub fn gt(&self, other: &NonZeroU16) -> bool`[src]

`pub fn ge(&self, other: &NonZeroU16) -> bool`[src]

`impl<T> PartialOrd<Wrapping<T>> for Wrapping<T> where T: PartialOrd<T>,` [src]

`pub fn partial_cmp(&self, other: &Wrapping<T>) -> Option<Ordering>`[src]

`pub fn lt(&self, other: &Wrapping<T>) -> bool`[src]

`pub fn le(&self, other: &Wrapping<T>) -> bool`[src]

`pub fn gt(&self, other: &Wrapping<T>) -> bool`[src]

`pub fn ge(&self, other: &Wrapping<T>) -> bool`[src]

`impl<'a> PartialOrd<Location<'a>> for Location<'a>`[src]

`pub fn partial_cmp(&self, other: &Location<'a>) -> Option<Ordering>`[src]

`pub fn lt(&self, other: &Location<'a>) -> bool`[src]

`pub fn le(&self, other: &Location<'a>) -> bool`[src]

`pub fn gt(&self, other: &Location<'a>) -> bool`[src]

`pub fn ge(&self, other: &Location<'a>) -> bool`[src]

`impl PartialOrd<TypeId> for TypeId`[src]

`pub fn partial_cmp(&self, other: &TypeId) -> Option<Ordering>`[src]

`pub fn lt(&self, other: &TypeId) -> bool`[src]

`pub fn le(&self, other: &TypeId) -> bool`[src]

`pub fn gt(&self, other: &TypeId) -> bool`[src]

`pub fn ge(&self, other: &TypeId) -> bool`[src]

`impl<T> PartialOrd<PhantomData<T>> for PhantomData<T> where T: ?Sized,` [src]

`pub fn partial_cmp(&self, _other: &PhantomData<T>) -> Option<Ordering>`[src]

`impl PartialOrd<NonZeroI64> for NonZeroI64`[src]

`pub fn partial_cmp(&self, other: &NonZeroI64) -> Option<Ordering>`[src]

`pub fn lt(&self, other: &NonZeroI64) -> bool`[src]

`pub fn le(&self, other: &NonZeroI64) -> bool`[src]

`pub fn gt(&self, other: &NonZeroI64) -> bool`[src]

`pub fn ge(&self, other: &NonZeroI64) -> bool`[src]

`impl PartialOrd<Error> for Error`[src]

`pub fn partial_cmp(&self, other: &Error) -> Option<Ordering>`[src]

`impl PartialOrd<NonZeroIsize> for NonZeroIsize`[src]

`pub fn partial_cmp(&self, other: &NonZeroIsize) -> Option<Ordering>`[src]

`pub fn lt(&self, other: &NonZeroIsize) -> bool`[src]

`pub fn le(&self, other: &NonZeroIsize) -> bool`[src]

`pub fn gt(&self, other: &NonZeroIsize) -> bool`[src]