# Struct bevy::math::prelude::CubicCurve

``````pub struct CubicCurve<P>where
P: VectorSpace,{
pub segments: Vec<CubicSegment<P>>,
}``````
Expand description

A collection of `CubicSegment`s chained into a single parametric curve. Has domain `[0, N)` where `N` is the number of attached segments.

Use any struct that implements the `CubicGenerator` trait to create a new curve, such as `CubicBezier`.

## Fields§

§`segments: Vec<CubicSegment<P>>`

Segments of the curve

## Implementations§

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### impl<P> CubicCurve<P>where P: VectorSpace,

#### pub fn position(&self, t: f32) -> P

Compute the position of a point on the cubic curve at the parametric value `t`.

Note that `t` varies from `0..=(n_points - 3)`.

##### Examples found in repository?
examples/animation/color_animation.rs (line 108)
```99
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```
``````fn animate_curve<T: CurveColor>(
time: Res<Time>,
mut query: Query<(&mut Transform, &mut Sprite, &Curve<T>)>,
) {
let t = (time.elapsed_seconds().sin() + 1.) / 2.;

for (mut transform, mut sprite, cubic_curve) in &mut query {
// position takes a point from the curve where 0 is the initial point
// and 1 is the last point
sprite.color = cubic_curve.0.position(t).into();
transform.translation.x = 600. * (t - 0.5);
}
}``````
More examples
examples/animation/cubic_curve.rs (line 84)
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```
``````fn animate_cube(time: Res<Time>, mut query: Query<(&mut Transform, &Curve)>, mut gizmos: Gizmos) {
let t = (time.elapsed_seconds().sin() + 1.) / 2.;

for (mut transform, cubic_curve) in &mut query {
// Draw the curve
gizmos.linestrip(cubic_curve.0.iter_positions(50), WHITE);
// position takes a point from the curve where 0 is the initial point
// and 1 is the last point
transform.translation = cubic_curve.0.position(t);
}
}``````

#### pub fn velocity(&self, t: f32) -> P

Compute the first derivative with respect to t at `t`. This is the instantaneous velocity of a point on the cubic curve at `t`.

Note that `t` varies from `0..=(n_points - 3)`.

#### pub fn acceleration(&self, t: f32) -> P

Compute the second derivative with respect to t at `t`. This is the instantaneous acceleration of a point on the cubic curve at `t`.

Note that `t` varies from `0..=(n_points - 3)`.

#### pub fn iter_samples<'a, 'b>( &'b self, subdivisions: usize, sample_function: impl FnMut(&CubicCurve<P>, f32) -> P + 'a, ) -> impl Iterator<Item = P> + 'awhere 'b: 'a,

A flexible iterator used to sample curves with arbitrary functions.

This splits the curve into `subdivisions` of evenly spaced `t` values across the length of the curve from start (t = 0) to end (t = n), where `n = self.segment_count()`, returning an iterator evaluating the curve with the supplied `sample_function` at each `t`.

For `subdivisions = 2`, this will split the curve into two lines, or three points, and return an iterator with 3 items, the three points, one at the start, middle, and end.

#### pub fn segments(&self) -> &[CubicSegment<P>]

The list of segments contained in this `CubicCurve`.

This spline’s global `t` value is equal to how many segments it has.

All method accepting `t` on `CubicCurve` depends on the global `t`. When sampling over the entire curve, you should either use one of the `iter_*` methods or account for the segment count using `curve.segments().len()`.

#### pub fn iter_positions(&self, subdivisions: usize) -> impl Iterator<Item = P>

Iterate over the curve split into `subdivisions`, sampling the position at each step.

##### Examples found in repository?
examples/animation/cubic_curve.rs (line 81)
```76
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```
``````fn animate_cube(time: Res<Time>, mut query: Query<(&mut Transform, &Curve)>, mut gizmos: Gizmos) {
let t = (time.elapsed_seconds().sin() + 1.) / 2.;

for (mut transform, cubic_curve) in &mut query {
// Draw the curve
gizmos.linestrip(cubic_curve.0.iter_positions(50), WHITE);
// position takes a point from the curve where 0 is the initial point
// and 1 is the last point
transform.translation = cubic_curve.0.position(t);
}
}``````

#### pub fn iter_velocities(&self, subdivisions: usize) -> impl Iterator<Item = P>

Iterate over the curve split into `subdivisions`, sampling the velocity at each step.

#### pub fn iter_accelerations(&self, subdivisions: usize) -> impl Iterator<Item = P>

Iterate over the curve split into `subdivisions`, sampling the acceleration at each step.

#### pub fn push_segment(&mut self, segment: CubicSegment<P>)

Adds a segment to the curve

## Trait Implementations§

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### impl<P> Clone for CubicCurve<P>where P: Clone + VectorSpace,

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#### fn clone(&self) -> CubicCurve<P>

Returns a copy of the value. Read more
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#### fn clone_from(&mut self, source: &Self)

Performs copy-assignment from `source`. Read more
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### impl<P> Debug for CubicCurve<P>where P: Debug + VectorSpace,

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#### fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter. Read more
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### impl<P> Extend<CubicSegment<P>> for CubicCurve<P>where P: VectorSpace,

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#### fn extend<T>(&mut self, iter: T)where T: IntoIterator<Item = CubicSegment<P>>,

Extends a collection with the contents of an iterator. Read more
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#### fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (`extend_one`)
Extends a collection with exactly one element.
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#### fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (`extend_one`)
Reserves capacity in a collection for the given number of additional elements. Read more
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### impl<P> From<CubicCurve<P>> for RationalCurve<P>where P: VectorSpace,

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#### fn from(value: CubicCurve<P>) -> RationalCurve<P>

Converts to this type from the input type.
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### impl<P> FromReflect for CubicCurve<P>where P: VectorSpace + TypePath, CubicCurve<P>: Any + Send + Sync, Vec<CubicSegment<P>>: FromReflect + TypePath + RegisterForReflection,

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#### fn from_reflect(reflect: &(dyn Reflect + 'static)) -> Option<CubicCurve<P>>

Constructs a concrete instance of `Self` from a reflected value.
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#### fn take_from_reflect( reflect: Box<dyn Reflect>, ) -> Result<Self, Box<dyn Reflect>>

Attempts to downcast the given value to `Self` using, constructing the value using `from_reflect` if that fails. Read more
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### impl<P> GetTypeRegistration for CubicCurve<P>where P: VectorSpace + TypePath, CubicCurve<P>: Any + Send + Sync, Vec<CubicSegment<P>>: FromReflect + TypePath + RegisterForReflection,

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#### fn get_type_registration() -> TypeRegistration

Returns the default `TypeRegistration` for this type.
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#### fn register_type_dependencies(registry: &mut TypeRegistry)

Registers other types needed by this type. Read more
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### impl<P> IntoIterator for CubicCurve<P>where P: VectorSpace,

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#### type IntoIter = <Vec<CubicSegment<P>> as IntoIterator>::IntoIter

Which kind of iterator are we turning this into?
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#### type Item = CubicSegment<P>

The type of the elements being iterated over.
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#### fn into_iter(self) -> <CubicCurve<P> as IntoIterator>::IntoIter

Creates an iterator from a value. Read more
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### impl<P> PartialEq for CubicCurve<P>where P: PartialEq + VectorSpace,

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#### fn eq(&self, other: &CubicCurve<P>) -> bool

This method tests for `self` and `other` values to be equal, and is used by `==`.
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#### fn ne(&self, other: &Rhs) -> bool

This method tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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### impl<P> Reflect for CubicCurve<P>where P: VectorSpace + TypePath, CubicCurve<P>: Any + Send + Sync, Vec<CubicSegment<P>>: FromReflect + TypePath + RegisterForReflection,

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#### fn get_represented_type_info(&self) -> Option<&'static TypeInfo>

Returns the `TypeInfo` of the type represented by this value. Read more
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#### fn into_any(self: Box<CubicCurve<P>>) -> Box<dyn Any>

Returns the value as a `Box<dyn Any>`.
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#### fn as_any(&self) -> &(dyn Any + 'static)

Returns the value as a `&dyn Any`.
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#### fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)

Returns the value as a `&mut dyn Any`.
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#### fn into_reflect(self: Box<CubicCurve<P>>) -> Box<dyn Reflect>

Casts this type to a boxed reflected value.
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#### fn as_reflect(&self) -> &(dyn Reflect + 'static)

Casts this type to a reflected value.
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#### fn as_reflect_mut(&mut self) -> &mut (dyn Reflect + 'static)

Casts this type to a mutable reflected value.
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#### fn clone_value(&self) -> Box<dyn Reflect>

Clones the value as a `Reflect` trait object. Read more
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#### fn set(&mut self, value: Box<dyn Reflect>) -> Result<(), Box<dyn Reflect>>

Performs a type-checked assignment of a reflected value to this value. Read more
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#### fn try_apply( &mut self, value: &(dyn Reflect + 'static), ) -> Result<(), ApplyError>

Tries to `apply` a reflected value to this value. Read more
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#### fn reflect_kind(&self) -> ReflectKind

Returns a zero-sized enumeration of “kinds” of type. Read more
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#### fn reflect_ref(&self) -> ReflectRef<'_>

Returns an immutable enumeration of “kinds” of type. Read more
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#### fn reflect_mut(&mut self) -> ReflectMut<'_>

Returns a mutable enumeration of “kinds” of type. Read more
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#### fn reflect_owned(self: Box<CubicCurve<P>>) -> ReflectOwned

Returns an owned enumeration of “kinds” of type. Read more
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#### fn reflect_partial_eq(&self, value: &(dyn Reflect + 'static)) -> Option<bool>

Returns a “partial equality” comparison result. Read more
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#### fn debug(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Debug formatter for the value. Read more
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#### fn apply(&mut self, value: &(dyn Reflect + 'static))

Applies a reflected value to this value. Read more
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#### fn reflect_hash(&self) -> Option<u64>

Returns a hash of the value (which includes the type). Read more
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#### fn serializable(&self) -> Option<Serializable<'_>>

Returns a serializable version of the value. Read more
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#### fn is_dynamic(&self) -> bool

Indicates whether or not this type is a dynamic type. Read more
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### impl<P> Struct for CubicCurve<P>where P: VectorSpace + TypePath, CubicCurve<P>: Any + Send + Sync, Vec<CubicSegment<P>>: FromReflect + TypePath + RegisterForReflection,

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#### fn field(&self, name: &str) -> Option<&(dyn Reflect + 'static)>

Returns a reference to the value of the field named `name` as a `&dyn Reflect`.
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#### fn field_mut(&mut self, name: &str) -> Option<&mut (dyn Reflect + 'static)>

Returns a mutable reference to the value of the field named `name` as a `&mut dyn Reflect`.
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#### fn field_at(&self, index: usize) -> Option<&(dyn Reflect + 'static)>

Returns a reference to the value of the field with index `index` as a `&dyn Reflect`.
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#### fn field_at_mut(&mut self, index: usize) -> Option<&mut (dyn Reflect + 'static)>

Returns a mutable reference to the value of the field with index `index` as a `&mut dyn Reflect`.
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#### fn name_at(&self, index: usize) -> Option<&str>

Returns the name of the field with index `index`.
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#### fn field_len(&self) -> usize

Returns the number of fields in the struct.
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#### fn iter_fields(&self) -> FieldIter<'_> ⓘ

Returns an iterator over the values of the reflectable fields for this struct.
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#### fn clone_dynamic(&self) -> DynamicStruct

Clones the struct into a `DynamicStruct`.
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### impl<P> TypePath for CubicCurve<P>where P: VectorSpace + TypePath, CubicCurve<P>: Any + Send + Sync,

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#### fn type_path() -> &'static str

Returns the fully qualified path of the underlying type. Read more
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#### fn short_type_path() -> &'static str

Returns a short, pretty-print enabled path to the type. Read more
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#### fn type_ident() -> Option<&'static str>

Returns the name of the type, or `None` if it is anonymous. Read more
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#### fn crate_name() -> Option<&'static str>

Returns the name of the crate the type is in, or `None` if it is anonymous. Read more
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#### fn module_path() -> Option<&'static str>

Returns the path to the module the type is in, or `None` if it is anonymous. Read more
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### impl<P> Typed for CubicCurve<P>where P: VectorSpace + TypePath, CubicCurve<P>: Any + Send + Sync, Vec<CubicSegment<P>>: FromReflect + TypePath + RegisterForReflection,

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#### fn type_info() -> &'static TypeInfo

Returns the compile-time info for the underlying type.
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### impl<T> Any for Twhere T: 'static + ?Sized,

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#### fn type_id(&self) -> TypeId

Gets the `TypeId` of `self`. Read more
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#### fn as_bind_group_shader_type(&self, _images: &RenderAssets<GpuImage>) -> U

Return the `T` `ShaderType` for `self`. When used in `AsBindGroup` derives, it is safe to assume that all images in `self` exist.
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#### fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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#### fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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### impl<T> Downcast for Twhere T: Any,

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#### fn into_any(self: Box<T>) -> Box<dyn Any>

Convert `Box<dyn Trait>` (where `Trait: Downcast`) to `Box<dyn Any>`. `Box<dyn Any>` can then be further `downcast` into `Box<ConcreteType>` where `ConcreteType` implements `Trait`.
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#### fn into_any_rc(self: Rc<T>) -> Rc<dyn Any>

Convert `Rc<Trait>` (where `Trait: Downcast`) to `Rc<Any>`. `Rc<Any>` can then be further `downcast` into `Rc<ConcreteType>` where `ConcreteType` implements `Trait`.
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#### fn as_any(&self) -> &(dyn Any + 'static)

Convert `&Trait` (where `Trait: Downcast`) to `&Any`. This is needed since Rust cannot generate `&Any`’s vtable from `&Trait`’s.
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#### fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)

Convert `&mut Trait` (where `Trait: Downcast`) to `&Any`. This is needed since Rust cannot generate `&mut Any`’s vtable from `&mut Trait`’s.
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#### fn into_any_arc(self: Arc<T>) -> Arc<dyn Any + Sync + Send>

Convert `Arc<Trait>` (where `Trait: Downcast`) to `Arc<Any>`. `Arc<Any>` can then be further `downcast` into `Arc<ConcreteType>` where `ConcreteType` implements `Trait`.
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#### fn from(t: T) -> T

Returns the argument unchanged.

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### impl<S> GetField for Swhere S: Struct,

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#### fn get_field<T>(&self, name: &str) -> Option<&T>where T: Reflect,

Returns a reference to the value of the field named `name`, downcast to `T`.
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Returns a mutable reference to the value of the field named `name`, downcast to `T`.
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#### fn reflect_path<'p>( &self, path: impl ReflectPath<'p>, ) -> Result<&(dyn Reflect + 'static), ReflectPathError<'p>>

Returns a reference to the value specified by `path`. Read more
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#### fn reflect_path_mut<'p>( &mut self, path: impl ReflectPath<'p>, ) -> Result<&mut (dyn Reflect + 'static), ReflectPathError<'p>>

Returns a mutable reference to the value specified by `path`. Read more
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#### fn path<'p, T>( &self, path: impl ReflectPath<'p>, ) -> Result<&T, ReflectPathError<'p>>where T: Reflect,

Returns a statically typed reference to the value specified by `path`. Read more
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#### fn path_mut<'p, T>( &mut self, path: impl ReflectPath<'p>, ) -> Result<&mut T, ReflectPathError<'p>>where T: Reflect,

Returns a statically typed mutable reference to the value specified by `path`. Read more
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#### fn instrument(self, span: Span) -> Instrumented<Self> ⓘ

Instruments this type with the provided `Span`, returning an `Instrumented` wrapper. Read more
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Instruments this type with the current `Span`, returning an `Instrumented` wrapper. Read more
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#### fn into(self) -> U

Calls `U::from(self)`.

That is, this conversion is whatever the implementation of `From<T> for U` chooses to do.

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#### fn into_either(self, into_left: bool) -> Either<Self, Self> ⓘ

Converts `self` into a `Left` variant of `Either<Self, Self>` if `into_left` is `true`. Converts `self` into a `Right` variant of `Either<Self, Self>` otherwise. Read more
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Converts `self` into a `Left` variant of `Either<Self, Self>` if `into_left(&self)` returns `true`. Converts `self` into a `Right` variant of `Either<Self, Self>` otherwise. Read more
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### impl<T> Pointable for T

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#### const ALIGN: usize = _

The alignment of pointer.
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#### type Init = T

The type for initializers.
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#### unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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Dereferences the given pointer. Read more
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Mutably dereferences the given pointer. Read more
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Drops the object pointed to by the given pointer. Read more
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### impl<T> Same for T

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#### type Output = T

Should always be `Self`
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### impl<T> ToOwned for Twhere T: Clone,

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#### type Owned = T

The resulting type after obtaining ownership.
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#### fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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Uses borrowed data to replace owned data, usually by cloning. Read more
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#### type Error = Infallible

The type returned in the event of a conversion error.
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Performs the conversion.
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#### type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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Performs the conversion.
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#### fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self> ⓘwhere S: Into<Dispatch>,

Attaches the provided `Subscriber` to this type, returning a `WithDispatch` wrapper. Read more
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