Enum EitherCart

pub enum EitherCart<C0, C1> {
    A(C0),
    B(C1),
}

A cart that can be one type or the other. Enables ergonomic polymorphic carts.

EitherCart enables yokes originating from different data sources and therefore having different cart types to be merged into the same yoke type, but still being able to recover the original cart type if necessary.

All relevant Cart traits are implemented for EitherCart, and carts can be safely wrapped in an EitherCart.

Also see Yoke::erase_box_cart().

Examples

use std::rc::Rc;
use yoke::either::EitherCart;
use yoke::Yoke;

let y1: Yoke<&'static str, Rc<str>> =
    Yoke::attach_to_zero_copy_cart("reference counted hello world".into());

let y2: Yoke<&'static str, &str> = Yoke::attach_to_zero_copy_cart("borrowed hello world");

type CombinedYoke<'a> = Yoke<&'static str, EitherCart<Rc<str>, &'a str>>;

// Both yokes can be combined into a single yoke type despite different carts
let y3: CombinedYoke = y1.wrap_cart_in_either_a();
let y4: CombinedYoke = y2.wrap_cart_in_either_b();

assert_eq!(*y3.get(), "reference counted hello world");
assert_eq!(*y4.get(), "borrowed hello world");

// The resulting yoke is cloneable if both cart types implement CloneableCart
let y5 = y4.clone();
assert_eq!(*y5.get(), "borrowed hello world");

Variants

A(C0)

B(C1)

Trait Implementations

impl<C0: Clone, C1: Clone> Clone for EitherCart<C0, C1>

fn clone(&self) -> EitherCart<C0, C1>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<C0: Debug, C1: Debug> Debug for EitherCart<C0, C1>

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

Formats the value using the given formatter.

impl<C0, C1, T> Deref for EitherCart<C0, C1>

where C0: Deref<Target = T>, C1: Deref<Target = T>,

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &T

Dereferences the value.

impl<C0: PartialEq, C1: PartialEq> PartialEq for EitherCart<C0, C1>

fn eq(&self, other: &EitherCart<C0, C1>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<C0, C1> CloneableCart for EitherCart<C0, C1>

where C0: CloneableCart, C1: CloneableCart,

impl<C0: Eq, C1: Eq> Eq for EitherCart<C0, C1>

impl<C0, C1, T> StableDeref for EitherCart<C0, C1>

where C0: StableDeref + Deref<Target = T>, C1: StableDeref + Deref<Target = T>,

impl<C0, C1> StructuralPartialEq for EitherCart<C0, C1>