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/*
* esodata - data structures and other things, 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;
/**
* A type-invariant lens for mutating objects.
*
* Note that there is no type-variant version, because that wouldn't make much sense.
*
* Also, mixing mutable and immutable lenses may lead to confusion.
*
* @author bjcul
*
* @param <Whole> The type the lens is used on
* @param <Part> The type the lens is focused on
*/
public interface MutableLens<Whole, Part> extends Lens<Whole, Part> {
/**
* Apply a mutation to an item.
*
* @param source The item to use the lens on.
* @param val The new value for the focused field.
*/
void mutate(Whole source, Part val);
@Override
default Whole set(Whole source, Part val) {
mutate(source, val);
return source;
}
}
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