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/*
* esodata - data structures of varying utility
* Copyright 2022, Ben Culkin
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
package bjc.optics;
import java.util.function.Function;
import bjc.data.Either;
import bjc.typeclasses.BiContainer;
/**
* A type-invariant prism
*
* @author bjcul
*
* @param <Whole> The type of the whole
* @param <Part> The type of the part
*/
public interface Prism<Whole, Part>
extends PrismX<Whole, Whole, Part, Part>, BiContainer<Whole, Part, Prism<Whole, Part>> {
/**
* Create a type-invariant prism from its component parts.
*
* @param <Whole> The type of the whole
* @param <Part> The type of the part
*
* @param f The 'match' function of the prism
* @param g The 'build' function of the prism
*
* @return The prism composed of the given parts.
*/
static <Whole, Part> Prism<Whole, Part> of(Function<Part, Either<Part, Whole>> f, Function<Whole, Part> g) {
return new FunctionalPrism<>(g, f);
}
}
final class FunctionalPrism<Whole, Part> implements Prism<Whole, Part> {
private final Function<Whole, Part> g;
private final Function<Part, Either<Part, Whole>> f;
public FunctionalPrism(Function<Whole, Part> g, Function<Part, Either<Part, Whole>> f) {
this.g = g;
this.f = f;
}
@Override
public Part build(Whole whole) {
return g.apply(whole);
}
@Override
public Either<Part, Whole> match(Part part) {
return f.apply(part);
}
}
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