yoke/
zero_from.rs

1// This file is part of ICU4X. For terms of use, please see the file
2// called LICENSE at the top level of the ICU4X source tree
3// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
4
5use crate::Yoke;
6use crate::Yokeable;
7
8use core::ops::Deref;
9use stable_deref_trait::StableDeref;
10
11use crate::ZeroFrom;
12
13impl<Y, C> Yoke<Y, C>
14where
15    Y: for<'a> Yokeable<'a>,
16    for<'a> <Y as Yokeable<'a>>::Output: ZeroFrom<'a, <C as Deref>::Target>,
17    C: StableDeref + Deref,
18    <C as Deref>::Target: 'static,
19{
20    /// Construct a [`Yoke`]`<Y, C>` from a cart implementing `StableDeref` by zero-copy cloning
21    /// the cart to `Y` and then yokeing that object to the cart.
22    ///
23    /// The type `Y` must implement [`ZeroFrom`]`<C::Target>`. This trait is auto-implemented
24    /// on many common types and can be custom implemented or derived in order to make it easier
25    /// to construct a `Yoke`.
26    ///
27    /// # Example
28    ///
29    /// Attach to a cart:
30    ///
31    /// ```
32    /// use std::borrow::Cow;
33    /// use yoke::Yoke;
34    ///
35    /// let yoke = Yoke::<Cow<'static, str>, String>::attach_to_zero_copy_cart(
36    ///     "demo".to_owned(),
37    /// );
38    ///
39    /// assert_eq!("demo", yoke.get());
40    /// ```
41    pub fn attach_to_zero_copy_cart(cart: C) -> Self {
42        Yoke::<Y, C>::attach_to_cart(cart, |c| <Y as Yokeable>::Output::zero_from(c))
43    }
44}