Trait std_prelude::Ord 1.0.0
[−]
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pub trait Ord: Eq + PartialOrd<Self> { fn cmp(&self, other: &Self) -> Ordering; fn max(self, other: Self) -> Self { ... } fn min(self, other: Self) -> Self { ... } }
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. 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: &Person) -> Ordering { self.height.cmp(&other.height) } } impl PartialOrd for Person { fn partial_cmp(&self, other: &Person) -> Option<Ordering> { Some(self.cmp(other)) } } impl PartialEq for Person { fn eq(&self, other: &Person) -> bool { self.height == other.height } }
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);
Provided Methods
fn max(self, other: Self) -> Self
1.22.0
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));
fn min(self, other: Self) -> Self
1.22.0
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));
Implementations on Foreign Types
impl Ord for UnicodeVersion
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impl<T> Ord for [T; 0] where
T: Ord,
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T: Ord,
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<T> Ord for [T; 7] where
T: Ord,
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T: Ord,
impl<Ret, A, B, C, D> Ord for fn(A, B, C, D) -> Ret
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impl Ord for u16
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impl<A, B, C, D, E, F, G, H, I, J, K> Ord for (A, B, C, D, E, F, G, H, I, J, K) where
A: Ord,
B: Ord,
C: Ord,
D: Ord,
E: Ord,
F: Ord,
G: Ord,
H: Ord,
I: Ord,
J: Ord,
K: Ord + ?Sized,
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A: Ord,
B: Ord,
C: Ord,
D: Ord,
E: Ord,
F: Ord,
G: Ord,
H: Ord,
I: Ord,
J: Ord,
K: Ord + ?Sized,
impl<Ret> Ord for unsafe extern "C" fn() -> Ret
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impl Ord for bool
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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<T> Ord for [T; 10] where
T: Ord,
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T: Ord,
impl<T> Ord for [T; 25] where
T: Ord,
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T: Ord,
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<T> Ord for [T; 8] where
T: Ord,
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T: Ord,
impl<Ret> Ord for fn() -> Ret
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impl<Ret, A, B> Ord for unsafe fn(A, B) -> Ret
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impl Ord for TypeId
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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<T> Ord for [T; 9] where
T: Ord,
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T: Ord,
impl<T> Ord for [T] where
T: Ord,
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T: Ord,
Implements comparison of vectors lexicographically.
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<A, B, C, D> Ord for (A, B, C, D) where
A: Ord,
B: Ord,
C: Ord,
D: Ord + ?Sized,
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A: Ord,
B: Ord,
C: Ord,
D: Ord + ?Sized,
impl<Ret, A> Ord for unsafe fn(A) -> Ret
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impl Ord for u32
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impl<A, B, C, D, E, F, G, H, I> Ord for (A, B, C, D, E, F, G, H, I) where
A: Ord,
B: Ord,
C: Ord,
D: Ord,
E: Ord,
F: Ord,
G: Ord,
H: Ord,
I: Ord + ?Sized,
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A: Ord,
B: Ord,
C: Ord,
D: Ord,
E: Ord,
F: Ord,
G: Ord,
H: Ord,
I: Ord + ?Sized,
impl<T> Ord for Reverse<T> where
T: Ord,
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T: Ord,
impl<T> Ord for [T; 11] where
T: Ord,
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T: Ord,
impl<T> Ord for *const T where
T: ?Sized,
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T: ?Sized,
impl<A, B, C, D, E, F> Ord for (A, B, C, D, E, F) where
A: Ord,
B: Ord,
C: Ord,
D: Ord,
E: Ord,
F: Ord + ?Sized,
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A: Ord,
B: Ord,
C: Ord,
D: Ord,
E: Ord,
F: Ord + ?Sized,
impl<Ret, A, B> Ord for fn(A, B) -> Ret
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impl<T> Ord for [T; 30] where
T: Ord,
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T: Ord,
impl<Ret, A> Ord for unsafe extern "C" fn(A) -> Ret
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impl<A, B, C, D, E, F, G, H> Ord for (A, B, C, D, E, F, G, H) where
A: Ord,
B: Ord,
C: Ord,
D: Ord,
E: Ord,
F: Ord,
G: Ord,
H: Ord + ?Sized,
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A: Ord,
B: Ord,
C: Ord,
D: Ord,
E: Ord,
F: Ord,
G: Ord,
H: Ord + ?Sized,
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, 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> Ord for fn(A, B, C, D, E, F, G, H) -> Ret
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impl Ord for i32
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impl<T> Ord for Option<T> where
T: Ord,
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T: Ord,
impl<Ret, A> Ord for fn(A) -> 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, D> Ord for unsafe fn(A, B, C, D) -> Ret
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impl<A, B, C, D, E, F, G, H, I, J> Ord for (A, B, C, D, E, F, G, H, I, J) where
A: Ord,
B: Ord,
C: Ord,
D: Ord,
E: Ord,
F: Ord,
G: Ord,
H: Ord,
I: Ord,
J: Ord + ?Sized,
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A: Ord,
B: Ord,
C: Ord,
D: Ord,
E: Ord,
F: Ord,
G: Ord,
H: Ord,
I: Ord,
J: Ord + ?Sized,
impl<T> Ord for [T; 1] where
T: Ord,
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T: Ord,
impl<'a, A> Ord for &'a mut A where
A: Ord + ?Sized,
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A: Ord + ?Sized,
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> Ord for unsafe fn(A, B, C, D, E, F, G) -> Ret
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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<T, E> Ord for Result<T, E> where
E: Ord,
T: Ord,
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E: Ord,
T: Ord,
impl<T> Ord for [T; 14] where
T: Ord,
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T: Ord,
impl<Ret, A> Ord for extern "C" fn(A) -> 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 Ord for i64
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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, 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 for [T; 5] where
T: Ord,
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T: Ord,
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<T> Ord for RefCell<T> where
T: Ord + ?Sized,
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T: Ord + ?Sized,
impl Ord for i16
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impl Ord for i8
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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, D, E> Ord for unsafe fn(A, B, C, D, E) -> 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<T> Ord for [T; 23] where
T: Ord,
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T: Ord,
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<T> Ord for [T; 3] where
T: Ord,
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T: Ord,
impl Ord for i128
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impl<T> Ord for Cell<T> where
T: Copy + Ord,
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T: Copy + Ord,
impl<T> Ord for [T; 17] where
T: Ord,
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T: Ord,
impl Ord for isize
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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> 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> Ord for extern "C" fn(A, B, C, D, E, F, G, H, ...) -> Ret
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impl<A, B> Ord for (A, B) where
A: Ord,
B: Ord + ?Sized,
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A: Ord,
B: Ord + ?Sized,
impl<T> Ord for PhantomData<T> where
T: ?Sized,
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T: ?Sized,
impl<A, B, C> Ord for (A, B, C) where
A: Ord,
B: Ord,
C: Ord + ?Sized,
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A: Ord,
B: Ord,
C: Ord + ?Sized,
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> Ord for unsafe extern "C" fn(A, B, C) -> Ret
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impl<T> Ord for [T; 21] where
T: Ord,
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T: Ord,
impl<T> Ord for [T; 6] where
T: Ord,
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T: Ord,
impl<T> Ord for [T; 16] where
T: Ord,
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T: Ord,
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> Ord for extern "C" fn(A, B, C, D) -> 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> Ord for extern "C" fn(A, B, ...) -> Ret
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impl<T> Ord for [T; 22] where
T: Ord,
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T: Ord,
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 unsafe extern "C" fn(A, B, C, D, E, F, G, ...) -> Ret
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impl<T> Ord for ManuallyDrop<T> where
T: Ord,
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T: Ord,
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<T> Ord for [T; 2] where
T: Ord,
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T: Ord,
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> Ord for fn(A, B, C, D, E, F) -> Ret
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impl<Ret, A> Ord for extern "C" fn(A, ...) -> Ret
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impl<T> Ord for [T; 29] where
T: Ord,
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T: Ord,
impl<'a, A> Ord for &'a A where
A: Ord + ?Sized,
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A: Ord + ?Sized,
impl<Ret, A, B, C> Ord for extern "C" fn(A, B, C, ...) -> Ret
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impl<A> Ord for (A,) where
A: Ord + ?Sized,
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A: Ord + ?Sized,
impl<Ret> Ord for unsafe fn() -> Ret
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impl<T> Ord for [T; 26] where
T: Ord,
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T: Ord,
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 Ord for u8
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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> Ord for extern "C" fn(A, B, C, D, E, F, G, H, I) -> Ret
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impl<Ret> Ord for extern "C" fn() -> 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<T> Ord for [T; 18] where
T: Ord,
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T: Ord,
impl Ord for ()
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impl<Ret, A, B> Ord for extern "C" fn(A, B) -> Ret
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impl<T> Ord for [T; 27] where
T: Ord,
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T: Ord,
impl<Ret, A, B, C> Ord for unsafe fn(A, B, C) -> 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
[src]
impl<T> Ord for [T; 15] where
T: Ord,
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T: Ord,
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
[src]
impl<Ret, A, B> Ord for unsafe extern "C" fn(A, B, ...) -> 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> Ord for unsafe extern "C" fn(A, B) -> 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<T> Ord for [T; 31] where
T: Ord,
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T: Ord,
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> Ord for unsafe extern "C" fn(A, B, C, D, E, ...) -> 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> Ord for extern "C" fn(A, B, C) -> 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 unsafe extern "C" fn(A, B, C, D, E) -> Ret
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impl<T> Ord for [T; 24] where
T: Ord,
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T: Ord,
impl<T> Ord for [T; 4] where
T: Ord,
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T: Ord,
impl<T> Ord for [T; 19] where
T: Ord,
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T: Ord,
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> Ord for unsafe extern "C" fn(A, B, C, D, E, F, G, H) -> Ret
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impl<T> Ord for [T; 28] where
T: Ord,
[src]
T: Ord,
impl<A, B, C, D, E, F, G, H, I, J, K, L> Ord for (A, B, C, D, E, F, G, H, I, J, K, L) where
A: Ord,
B: Ord,
C: Ord,
D: Ord,
E: Ord,
F: Ord,
G: Ord,
H: Ord,
I: Ord,
J: Ord,
K: Ord,
L: Ord + ?Sized,
[src]
A: Ord,
B: Ord,
C: Ord,
D: Ord,
E: Ord,
F: Ord,
G: Ord,
H: Ord,
I: Ord,
J: Ord,
K: Ord,
L: Ord + ?Sized,
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
[src]
impl<T> Ord for NonZero<T> where
T: Zeroable + Ord,
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T: Zeroable + Ord,
impl Ord for char
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impl<A, B, C, D, E> Ord for (A, B, C, D, E) where
A: Ord,
B: Ord,
C: Ord,
D: Ord,
E: Ord + ?Sized,
[src]
A: Ord,
B: Ord,
C: Ord,
D: Ord,
E: Ord + ?Sized,
impl<T> Ord for [T; 13] where
T: Ord,
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T: Ord,
impl<T> Ord for [T; 32] where
T: Ord,
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T: Ord,
impl<Ret, A> Ord for unsafe extern "C" fn(A, ...) -> 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<T> Ord for *mut T where
T: ?Sized,
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T: ?Sized,
impl Ord for u128
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impl<T> Ord for [T; 20] where
T: Ord,
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T: Ord,
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
[src]
impl<A, B, C, D, E, F, G> Ord for (A, B, C, D, E, F, G) where
A: Ord,
B: Ord,
C: Ord,
D: Ord,
E: Ord,
F: Ord,
G: Ord + ?Sized,
[src]
A: Ord,
B: Ord,
C: Ord,
D: Ord,
E: Ord,
F: Ord,
G: Ord + ?Sized,
impl Ord for u64
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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 Ord for Error
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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<T> Ord for [T; 12] where
T: Ord,
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T: Ord,
impl<T> Ord for Wrapping<T> where
T: Ord,
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T: Ord,
impl<Ret, A, B, C, D> Ord for extern "C" fn(A, B, C, D, ...) -> Ret
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impl Ord for usize
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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
[src]
impl<Ret, A, B, C, D, E> Ord for extern "C" fn(A, B, C, D, E) -> Ret
[src]
impl<Y, R> Ord for GeneratorState<Y, R> where
R: Ord,
Y: Ord,
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R: Ord,
Y: Ord,
impl<T> Ord for LinkedList<T> where
T: Ord,
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T: Ord,
impl<'a, B> Ord for Cow<'a, B> where
B: Ord + ToOwned + ?Sized,
[src]
B: Ord + ToOwned + ?Sized,
impl<T> Ord for Box<T> where
T: Ord + ?Sized,
[src]
T: Ord + ?Sized,
impl<A> Ord for VecDeque<A> where
A: Ord,
[src]
A: Ord,
impl<T> Ord for Vec<T> where
T: Ord,
[src]
T: Ord,
Implements ordering of vectors, lexicographically.
impl<T> Ord for BTreeSet<T> where
T: Ord,
[src]
T: Ord,