Expand description
Used to cast values.
This is a convenience trait to enable writing
src.az::<Dst>(). This would not work with
the Cast::cast method because
the Cast trait is generic while its cast method
is not generic.
This trait’s method is suitable for chaining.
If there is an implementation of
Cast<Dst> for &Src but not for Src,
and the variable src is of type Src, then
src.az::<Dst>() would not work and
(&src).az::<Dst>() is not easy to use with
chaining, but
src.borrow().az::<Dst>() works.
Panics
When debug assertions are enabled, this trait’s method panics if the
value does not fit in the destination. When debug assertions are not
enabled (usual in release mode), the wrapped value can be returned,
but it is not considered a breaking change if in the future it panics;
if wrapping is required use WrappingAs instead.
This trait’s method also panics with no debug assertions if the value does not fit and cannot be wrapped, for example when trying to cast floating-point ∞ into an integer type.
Examples
use az::Az;
assert_eq!(5i32.az::<u32>(), 5);
assert_eq!(17.1f32.az::<u8>(), 17);The following example shows how this trait can be used when Cast
is implemented for a reference type.
use az::{Az, Cast};
use core::borrow::Borrow;
struct I(i32);
impl Cast<i64> for &'_ I {
fn cast(self) -> i64 { self.0.cast() }
}
let r = &I(-5);
assert_eq!(r.az::<i64>(), -5);
let owned = I(12);
assert_eq!(owned.borrow().az::<i64>(), 12);