42 lines
838 B
Rust
42 lines
838 B
Rust
use crate::{Lens, LensOver, LensTrait, LensView};
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pub struct Combination<A, B>(A, B);
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impl<A, B> LensTrait for Combination<A, B> {}
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impl<A, B> std::ops::Add<Lens<B>> for Lens<A>
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where
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A: LensTrait,
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B: LensTrait,
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{
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type Output = Lens<Combination<Lens<A>, Lens<B>>>;
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fn add(self, rhs: Lens<B>) -> Self::Output {
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Lens(Combination(self, rhs))
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}
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}
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impl<A, B, T> LensView<T> for Combination<A, B>
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where
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A: LensView<T>,
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B: LensView<A::Field>,
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{
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type Field = B::Field;
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fn view(thing: T) -> Self::Field {
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B::view(A::view(thing))
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}
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}
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impl<A, B, T> LensOver<T> for Combination<A, B>
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where
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A: LensOver<T>,
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B: LensOver<A::Field>,
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{
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fn over<F>(thing: T, f: F) -> T
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where
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F: FnOnce(Self::Field) -> Self::Field,
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{
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A::over(thing, |b| B::over(b, f))
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}
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}
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