refraction 0.1.2

use super::{Compose, Identity, Invert, Iso, PartialLens};

/// The supertype of all prism families.
pub trait Prism: PartialLens
    where Self::AtInitial: Prism,
          Self::AtFinal: Prism
{
    fn inject(&self, v: Self::FinalTarget) -> Self::FinalSource;
}

impl<S, T> Prism for Identity<S, T> {
    #[inline]
    fn inject(&self, v: T) -> T {
        v
    }
}

impl<LF: Prism, LS: ?Sized> Prism for Compose<LF, LS>
    where LS: Prism<InitialTarget = LF::InitialSource, FinalTarget = LF::FinalSource>,
          LF::AtInitial: Prism,
          LF::AtFinal: Prism,
          LS::AtInitial: Prism,
          LS::AtFinal: Prism
{
    fn inject(&self, v: Self::FinalTarget) -> Self::FinalSource {
        self.second.inject(self.first.inject(v))
    }
}

impl<L: Iso> Prism for Invert<L>
    where L::AtInitial: Iso,
          L::AtFinal: Iso
{
    #[inline]
    fn inject(&self, v: Self::FinalTarget) -> Self::FinalSource {
        self.deinvert.get(v)
    }
}