Dreaded_X
668f13863a
With this trait the impl_cast macros are no longer needed, simplifying everything. This commit also improved how the actual casting itself is handled.
38 lines
606 B
Rust
38 lines
606 B
Rust
#![allow(incomplete_features)]
|
|
#![feature(specialization)]
|
|
#![feature(unsize)]
|
|
|
|
use std::marker::Unsize;
|
|
|
|
pub trait Cast<P: ?Sized> {
|
|
fn cast(&self) -> Option<&P>;
|
|
fn cast_mut(&mut self) -> Option<&mut P>;
|
|
}
|
|
|
|
impl<D, P> Cast<P> for D
|
|
where
|
|
P: ?Sized,
|
|
{
|
|
default fn cast(&self) -> Option<&P> {
|
|
None
|
|
}
|
|
|
|
default fn cast_mut(&mut self) -> Option<&mut P> {
|
|
None
|
|
}
|
|
}
|
|
|
|
impl<D, P> Cast<P> for D
|
|
where
|
|
D: Unsize<P>,
|
|
P: ?Sized,
|
|
{
|
|
fn cast(&self) -> Option<&P> {
|
|
Some(self)
|
|
}
|
|
|
|
fn cast_mut(&mut self) -> Option<&mut P> {
|
|
Some(self)
|
|
}
|
|
}
|