1.0.0[−][src]Trait core::cmp::Ord
Trait for types that form a total order.
An order is a total order if it is (for all a
, b
and c
):
- total and antisymmetric: exactly one of
a < b
,a == b
ora > b
is true; and - transitive,
a < b
andb < c
impliesa < 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 declaration 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 } }Run
Required methods
fn cmp(&self, other: &Self) -> Ordering
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);Run
Provided methods
fn max(self, other: Self) -> Self where
Self: Sized,
1.21.0
Self: Sized,
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));Run
fn min(self, other: Self) -> Self where
Self: Sized,
1.21.0
Self: Sized,
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));Run
fn clamp(self, min: Self, max: Self) -> Self where
Self: Sized,
Self: Sized,
Implementors
impl Ord for !
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impl Ord for ()
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impl Ord for Ordering
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impl Ord for Infallible
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impl Ord for TypeId
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impl Ord for CpuidResult
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fn cmp(&self, other: &CpuidResult) -> Ordering
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impl Ord for UnicodeVersion
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fn cmp(&self, other: &UnicodeVersion) -> Ordering
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impl Ord for Error
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impl Ord for PhantomPinned
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fn cmp(&self, other: &PhantomPinned) -> Ordering
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impl Ord for NonZeroI128
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fn cmp(&self, other: &NonZeroI128) -> Ordering
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impl Ord for NonZeroI16
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fn cmp(&self, other: &NonZeroI16) -> Ordering
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impl Ord for NonZeroI32
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fn cmp(&self, other: &NonZeroI32) -> Ordering
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impl Ord for NonZeroI64
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fn cmp(&self, other: &NonZeroI64) -> Ordering
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impl Ord for NonZeroI8
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impl Ord for NonZeroIsize
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fn cmp(&self, other: &NonZeroIsize) -> Ordering
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impl Ord for NonZeroU128
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fn cmp(&self, other: &NonZeroU128) -> Ordering
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impl Ord for NonZeroU16
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fn cmp(&self, other: &NonZeroU16) -> Ordering
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impl Ord for NonZeroU32
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fn cmp(&self, other: &NonZeroU32) -> Ordering
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impl Ord for NonZeroU64
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fn cmp(&self, other: &NonZeroU64) -> Ordering
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impl Ord for NonZeroU8
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impl Ord for NonZeroUsize
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fn cmp(&self, other: &NonZeroUsize) -> Ordering
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impl Ord for NoneError
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impl Ord for Duration
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impl Ord for bool
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impl Ord for char
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impl Ord for i8
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impl Ord for i16
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impl Ord for i32
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impl Ord for i64
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impl Ord for i128
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impl Ord for isize
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impl Ord for str
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Implements ordering of strings.
Strings are ordered lexicographically by their byte values. This orders Unicode code
points based on their positions in the code charts. This is not necessarily the same as
"alphabetical" order, which varies by language and locale. Sorting strings according to
culturally-accepted standards requires locale-specific data that is outside the scope of
the str
type.
impl Ord for u8
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impl Ord for u16
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impl Ord for u32
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impl Ord for u64
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impl Ord for u128
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impl Ord for usize
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impl<'_, A: ?Sized> Ord for &'_ A where
A: Ord,
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A: Ord,
impl<'_, A: ?Sized> Ord for &'_ mut A where
A: Ord,
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A: Ord,
impl<A> Ord for (A,) where
A: Ord + ?Sized,
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A: Ord + ?Sized,
impl<A: Ord, B> Ord for (A, B) where
B: Ord + ?Sized,
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B: Ord + ?Sized,
impl<A: Ord, B: Ord, C> Ord for (A, B, C) where
C: Ord + ?Sized,
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C: Ord + ?Sized,
impl<A: Ord, B: Ord, C: Ord, D> Ord for (A, B, C, D) where
D: Ord + ?Sized,
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D: Ord + ?Sized,
impl<A: Ord, B: Ord, C: Ord, D: Ord, E> Ord for (A, B, C, D, E) where
E: Ord + ?Sized,
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E: Ord + ?Sized,
impl<A: Ord, B: Ord, C: Ord, D: Ord, E: Ord, F> Ord for (A, B, C, D, E, F) where
F: Ord + ?Sized,
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F: Ord + ?Sized,
impl<A: Ord, B: Ord, C: Ord, D: Ord, E: Ord, F: Ord, G> Ord for (A, B, C, D, E, F, G) where
G: Ord + ?Sized,
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G: Ord + ?Sized,
impl<A: Ord, B: Ord, C: Ord, D: Ord, E: Ord, F: Ord, G: Ord, H> Ord for (A, B, C, D, E, F, G, H) where
H: Ord + ?Sized,
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H: Ord + ?Sized,
impl<A: Ord, B: Ord, C: Ord, D: Ord, E: Ord, F: Ord, G: Ord, H: Ord, I> Ord for (A, B, C, D, E, F, G, H, I) where
I: Ord + ?Sized,
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I: Ord + ?Sized,
impl<A: Ord, B: Ord, C: Ord, D: Ord, E: Ord, F: Ord, G: Ord, H: Ord, I: Ord, J> Ord for (A, B, C, D, E, F, G, H, I, J) where
J: Ord + ?Sized,
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J: Ord + ?Sized,
impl<A: Ord, B: Ord, C: Ord, D: Ord, E: Ord, F: Ord, G: Ord, H: Ord, I: Ord, J: Ord, K> Ord for (A, B, C, D, E, F, G, H, I, J, K) where
K: Ord + ?Sized,
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K: Ord + ?Sized,
impl<A: Ord, B: Ord, C: Ord, D: Ord, E: Ord, F: Ord, G: Ord, H: Ord, I: Ord, J: Ord, K: Ord, L> Ord for (A, B, C, D, E, F, G, H, I, J, K, L) where
L: Ord + ?Sized,
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L: Ord + ?Sized,
impl<P: Ord> Ord for Pin<P>
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impl<Ret> Ord for extern "C" fn() -> Ret
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impl<Ret> Ord for fn() -> Ret
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impl<Ret> Ord for unsafe extern "C" fn() -> Ret
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impl<Ret> Ord for unsafe fn() -> Ret
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impl<Ret, A> Ord for extern "C" fn(_: A) -> Ret
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impl<Ret, A> Ord for extern "C" fn(_: A, _: ...) -> Ret
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impl<Ret, A> Ord for fn(_: A) -> Ret
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impl<Ret, A> Ord for unsafe extern "C" fn(_: A) -> Ret
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impl<Ret, A> Ord for unsafe extern "C" fn(_: A, _: ...) -> Ret
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impl<Ret, A> Ord for unsafe fn(_: A) -> Ret
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impl<Ret, A, B> Ord for extern "C" fn(_: A, _: B) -> Ret
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impl<Ret, A, B> Ord for extern "C" fn(_: A, _: B, _: ...) -> Ret
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impl<Ret, A, B> Ord for fn(_: A, _: B) -> Ret
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impl<Ret, A, B> Ord for unsafe extern "C" fn(_: A, _: B) -> Ret
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impl<Ret, A, B> Ord for unsafe extern "C" fn(_: A, _: B, _: ...) -> Ret
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impl<Ret, A, B> Ord for unsafe fn(_: A, _: B) -> Ret
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impl<Ret, A, B, C> Ord for extern "C" fn(_: A, _: B, _: C) -> Ret
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impl<Ret, A, B, C> Ord for extern "C" fn(_: A, _: B, _: C, _: ...) -> Ret
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impl<Ret, A, B, C> Ord for fn(_: A, _: B, _: C) -> Ret
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impl<Ret, A, B, C> Ord for unsafe extern "C" fn(_: A, _: B, _: C) -> Ret
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impl<Ret, A, B, C> Ord for unsafe extern "C" fn(_: A, _: B, _: C, _: ...) -> Ret
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impl<Ret, A, B, C> Ord for unsafe fn(_: A, _: B, _: C) -> Ret
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impl<Ret, A, B, C, D> Ord for extern "C" fn(_: A, _: B, _: C, _: D) -> Ret
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impl<Ret, A, B, C, D> Ord for extern "C" fn(_: A, _: B, _: C, _: D, _: ...) -> Ret
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impl<Ret, A, B, C, D> Ord for fn(_: A, _: B, _: C, _: D) -> Ret
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impl<Ret, A, B, C, D> Ord for unsafe extern "C" fn(_: A, _: B, _: C, _: D) -> Ret
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impl<Ret, A, B, C, D> Ord for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: ...) -> Ret
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impl<Ret, A, B, C, D> Ord for unsafe fn(_: A, _: B, _: C, _: D) -> Ret
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impl<Ret, A, B, C, D, E> Ord for extern "C" fn(_: A, _: B, _: C, _: D, _: E) -> Ret
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impl<Ret, A, B, C, D, E> Ord for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: ...) -> Ret
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impl<Ret, A, B, C, D, E> Ord for fn(_: A, _: B, _: C, _: D, _: E) -> Ret
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impl<Ret, A, B, C, D, E> Ord for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E) -> Ret
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impl<Ret, A, B, C, D, E> Ord for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: ...) -> Ret
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impl<Ret, A, B, C, D, E> Ord for unsafe fn(_: A, _: B, _: C, _: D, _: E) -> Ret
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impl<Ret, A, B, C, D, E, F> Ord for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F) -> Ret
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impl<Ret, A, B, C, D, E, F> Ord for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: ...) -> Ret
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impl<Ret, A, B, C, D, E, F> Ord for fn(_: A, _: B, _: C, _: D, _: E, _: F) -> Ret
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impl<Ret, A, B, C, D, E, F> Ord for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F) -> Ret
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impl<Ret, A, B, C, D, E, F> Ord for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: ...) -> Ret
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impl<Ret, A, B, C, D, E, F> Ord for unsafe fn(_: A, _: B, _: C, _: D, _: E, _: F) -> Ret
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impl<Ret, A, B, C, D, E, F, G> Ord for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G) -> Ret
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impl<Ret, A, B, C, D, E, F, G> Ord for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: ...) -> Ret
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impl<Ret, A, B, C, D, E, F, G> Ord for fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G) -> Ret
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impl<Ret, A, B, C, D, E, F, G> Ord for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G) -> Ret
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impl<Ret, A, B, C, D, E, F, G> Ord for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: ...) -> Ret
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impl<Ret, A, B, C, D, E, F, G> Ord for unsafe fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H> Ord for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H> Ord for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: ...) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H> Ord for fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H> Ord for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H> Ord for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: ...) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H> Ord for unsafe fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I> Ord for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I> Ord for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: ...) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I> Ord for fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I> Ord for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I> Ord for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: ...) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I> Ord for unsafe fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J> Ord for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J> Ord for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: ...) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J> Ord for fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J> Ord for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J> Ord for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: ...) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J> Ord for unsafe fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Ord for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Ord for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: ...) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Ord for fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Ord for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Ord for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: ...) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Ord for unsafe fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Ord for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Ord for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L, _: ...) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Ord for fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L) -> Ret
[src]
impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Ord for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Ord for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L, _: ...) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Ord for unsafe fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L) -> Ret
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impl<T: Ord + Copy> Ord for Cell<T>
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impl<T: Ord + ?Sized> Ord for ManuallyDrop<T>
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fn cmp(&self, other: &ManuallyDrop<T>) -> Ordering
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impl<T: Ord> Ord for Option<T>
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impl<T: Ord> Ord for Poll<T>
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impl<T: Ord> Ord for Reverse<T>
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impl<T: Ord> Ord for Wrapping<T>
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impl<T: Ord> Ord for [T; 0]
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impl<T: Ord> Ord for [T; 1]
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impl<T: Ord> Ord for [T; 2]
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impl<T: Ord> Ord for [T; 3]
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impl<T: Ord> Ord for [T; 4]
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impl<T: Ord> Ord for [T; 5]
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impl<T: Ord> Ord for [T; 6]
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impl<T: Ord> Ord for [T; 7]
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impl<T: Ord> Ord for [T; 8]
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impl<T: Ord> Ord for [T; 9]
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impl<T: Ord> Ord for [T; 10]
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impl<T: Ord> Ord for [T; 11]
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impl<T: Ord> Ord for [T; 12]
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impl<T: Ord> Ord for [T; 13]
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impl<T: Ord> Ord for [T; 14]
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impl<T: Ord> Ord for [T; 15]
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impl<T: Ord> Ord for [T; 16]
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impl<T: Ord> Ord for [T; 17]
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impl<T: Ord> Ord for [T; 18]
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impl<T: Ord> Ord for [T; 19]
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impl<T: Ord> Ord for [T; 20]
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impl<T: Ord> Ord for [T; 21]
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impl<T: Ord> Ord for [T; 22]
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impl<T: Ord> Ord for [T; 23]
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impl<T: Ord> Ord for [T; 24]
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impl<T: Ord> Ord for [T; 25]
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impl<T: Ord> Ord for [T; 26]
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impl<T: Ord> Ord for [T; 27]
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impl<T: Ord> Ord for [T; 28]
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impl<T: Ord> Ord for [T; 29]
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impl<T: Ord> Ord for [T; 30]
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impl<T: Ord> Ord for [T; 31]
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impl<T: Ord> Ord for [T; 32]
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impl<T: Ord> Ord for [T]
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Implements comparison of vectors lexicographically.
impl<T: Ord, E: Ord> Ord for Result<T, E>
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impl<T: ?Sized + Ord> Ord for RefCell<T>
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fn cmp(&self, other: &RefCell<T>) -> Ordering
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Panics
Panics if the value in either RefCell
is currently borrowed.