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Mend

image_texel::layout

Trait Mend 

Source 
pub trait Mend<From> {
    type Into: Layout;

    // Required method
    fn mend(self, from: &From) -> Self::Into;
}
Expand description

Convert a layout to a stricter one.

§Design

A comment on the design space available for this trait.

(TODO: wrong) We require that the trait is implemented for the type that is returned. If we required that the trait be implemented for the receiver then this would restrict third-parties from using it to its full potential. In particular, since Mend is a foreign trait the coherence rules make it impossible to specify:

TODO Terminology: https://rust-lang.github.io/rfcs/2451-re-rebalancing-coherence.html

ⓘ
impl<T> Mend<LocalType> for T {}

TODO: rewrite this…

ⓘ
impl<T> Mend<T> for LocalType {}

The forms of evolution that we want to keep open:

  • Introduce a new form of mending between existing layouts. For example, a new color space transformation should be able to translate between existing types. Note that we will assume that in such a case the type parameters do not appear uncovered in the target or the source so that having either as the trait receiver (T0) allows this.
  • An upgrader type should be able to mend a <T: LocalOrForeignTrait> into a chosen layout.
  • TODO: When add a new layout type which mender types and targets do we want?

The exact form thus simply depends on expected use and the allow evolution for this crate. Consider in particular this coherence/SemVer rule:

Adding any impl with an uncovered type parameter is considered a major breaking change.

TODO

TODO: comment and consider &self.

Required Associated Types§

Source

type Into: Layout

Required Methods§

Source

fn mend(self, from: &From) -> Self::Into

Dyn Compatibility§

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors§