1.0.0[−][src]Trait nom::lib::std::prelude::v1::v1::PartialOrd

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

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

antisymmetry: 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 declaration 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);

Required methods

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

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 = std::f64::NAN.partial_cmp(&1.0);
assert_eq!(result, None);

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Provided methods

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

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] fn le(&self, other: &Rhs) -> bool`

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] fn gt(&self, other: &Rhs) -> bool`

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] fn ge(&self, other: &Rhs) -> bool`

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<'a, 'b> PartialOrd<Cow<'a, Path>> for Path`[src]

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

`impl PartialOrd<Ipv6Addr> for Ipv6Addr`[src]

`fn partial_cmp(&self, other: &Ipv6Addr) -> Option<Ordering>`[src]

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

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

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

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

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

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

`impl<'a, 'b> PartialOrd<Cow<'b, OsStr>> for &'a Path`[src]

`fn partial_cmp(&self, other: &Cow<'b, OsStr>) -> Option<Ordering>`[src]

`impl<'a, 'b> PartialOrd<Cow<'a, Path>> for &'b Path`[src]

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

`impl<'a, 'b> PartialOrd<OsString> for PathBuf`[src]

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

`impl<'a, 'b> PartialOrd<Cow<'a, Path>> for OsString`[src]

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

`impl<'a, 'b> PartialOrd<&'a Path> for PathBuf`[src]

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

`impl PartialOrd<IpAddr> for Ipv6Addr`[src]

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

`impl<'a, 'b> PartialOrd<OsStr> for PathBuf`[src]

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

`impl PartialOrd<IpAddr> for Ipv4Addr`[src]

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

`impl<'a, 'b> PartialOrd<Cow<'a, Path>> for OsStr`[src]

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

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

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

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

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

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

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

`impl<'a, 'b> PartialOrd<&'a OsStr> for Path`[src]

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

`impl<'a, 'b> PartialOrd<Cow<'a, Path>> for &'b OsStr`[src]

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

`impl<'a, 'b> PartialOrd<Cow<'a, OsStr>> for Path`[src]

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

`impl<'a, 'b> PartialOrd<Cow<'a, Path>> for PathBuf`[src]

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

`impl PartialOrd<Ipv4Addr> for IpAddr`[src]

`fn partial_cmp(&self, other: &Ipv4Addr) -> Option<Ordering>`[src]

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

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

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

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

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

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

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

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

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

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

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

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

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

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

`impl PartialOrd<Ipv4Addr> for Ipv4Addr`[src]

`fn partial_cmp(&self, other: &Ipv4Addr) -> Option<Ordering>`[src]

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

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

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

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

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

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

`impl<'a, 'b> PartialOrd<&'a OsStr> for OsString`[src]

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

`impl<'a, 'b> PartialOrd<OsStr> for OsString`[src]

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

`impl<'a, 'b> PartialOrd<&'a Path> for OsString`[src]

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

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

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

`impl<'a, 'b> PartialOrd<PathBuf> for Path`[src]

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

`impl<'a, 'b> PartialOrd<PathBuf> for OsString`[src]

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

`impl<'a, 'b> PartialOrd<Path> for OsString`[src]

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

`impl<'a, 'b> PartialOrd<Path> for PathBuf`[src]

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

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

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

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

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

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

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

`impl<'a, 'b> PartialOrd<Path> for OsStr`[src]

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

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

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

`impl<'a, 'b> PartialOrd<OsString> for Path`[src]

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

`impl PartialOrd<Ipv6Addr> for IpAddr`[src]

`fn partial_cmp(&self, other: &Ipv6Addr) -> Option<Ordering>`[src]

`impl<'a, 'b> PartialOrd<OsStr> for &'a Path`[src]

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

`impl<'a, 'b> PartialOrd<OsString> for OsStr`[src]

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

`impl<'a, 'b> PartialOrd<OsStr> for Path`[src]

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

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

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

`impl<'a, 'b> PartialOrd<Cow<'a, OsStr>> for PathBuf`[src]

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

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

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

`impl<'a, 'b> PartialOrd<&'a Path> for OsStr`[src]

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

`impl PartialOrd<str> for OsString`[src]

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

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

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

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

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

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

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

`impl<'a, 'b> PartialOrd<&'a OsStr> for PathBuf`[src]

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

`impl<'a, 'b> PartialOrd<Cow<'a, OsStr>> for OsString`[src]

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

`impl<'a, 'b> PartialOrd<OsString> for &'a OsStr`[src]

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

`impl<'a, 'b> PartialOrd<Cow<'a, OsStr>> for &'b OsStr`[src]

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

`impl<'a, 'b> PartialOrd<Path> for &'a OsStr`[src]

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

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

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

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

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

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

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

`impl<'a, 'b> PartialOrd<PathBuf> for OsStr`[src]

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

`impl<'a, 'b> PartialOrd<PathBuf> for &'a Path`[src]

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

`impl<'a, 'b> PartialOrd<PathBuf> for &'a OsStr`[src]

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

`impl<'a, 'b> PartialOrd<Cow<'a, OsStr>> for OsStr`[src]

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

`impl<'a, 'b> PartialOrd<OsString> for &'a Path`[src]

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

`impl PartialOrd<str> for OsStr`[src]

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

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

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

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

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

`impl<A, B> PartialOrd<(A, B)> for (A, B) where A: PartialEq<A> + PartialOrd<A>, B: PartialEq + PartialOrd + ?Sized,` [src]

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

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

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

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

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

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

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

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

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

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

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

`impl<Ret, A, B, C> PartialOrd<unsafe extern "C" fn(A, B, C) -> Ret> for unsafe extern "C" fn(A, B, C) -> Ret`[src]

`fn partial_cmp( &self, other: &unsafe extern "C" fn(A, B, C) -> Ret ) -> Option<Ordering>`[src]

`impl<Ret, A> PartialOrd<extern "C" fn(A) -> Ret> for extern "C" fn(A) -> Ret`[src]

`fn partial_cmp(&self, other: &extern "C" fn(A) -> Ret) -> Option<Ordering>`[src]

`impl<Ret, A, B, C, D, E, F, G, H, I> PartialOrd<unsafe fn(A, B, C, D, E, F, G, H, I) -> Ret> for unsafe fn(A, B, C, D, E, F, G, H, I) -> Ret`[src]

`fn partial_cmp( &self, other: &unsafe fn(A, B, C, D, E, F, G, H, I) -> Ret ) -> Option<Ordering>`[src]

`impl<Ret, A> PartialOrd<unsafe extern "C" fn(A) -> Ret> for unsafe extern "C" fn(A) -> Ret`[src]

`fn partial_cmp( &self, other: &unsafe extern "C" fn(A) -> Ret ) -> Option<Ordering>`[src]

`impl<Ret, A, B, C> PartialOrd<unsafe extern "C" fn(A, B, C, VaListImpl) -> Ret> for unsafe extern "C" fn(A, B, C, VaListImpl) -> Ret`[src]

`fn partial_cmp( &self, other: &unsafe extern "C" fn(A, B, C, VaListImpl) -> Ret ) -> Option<Ordering>`[src]

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

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

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

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

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

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

`impl<Ret, A, B, C, D> PartialOrd<unsafe extern "C" fn(A, B, C, D, VaListImpl) -> Ret> for unsafe extern "C" fn(A, B, C, D, VaListImpl) -> Ret`[src]

`fn partial_cmp( &self, other: &unsafe extern "C" fn(A, B, C, D, VaListImpl) -> Ret ) -> Option<Ordering>`[src]

`impl<T> PartialOrd<Cell<T>> for Cell<T> where T: Copy + PartialOrd<T>,` [src]

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

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

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

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