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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.functypes;
import java.util.function.BiFunction;
import java.util.function.Function;
/**
* Represents a function which takes 3 input values.
*
* @author bjcul
*
* @param <In1> The first input type
* @param <In2> The second input type
* @param <In3> The third input type
* @param <Out> The output type
*/
@FunctionalInterface
public interface TriFunction<In1, In2, In3, Out> {
/**
* Apply this function.
*
* @param x The first input
* @param y The second input
* @param z The third input
*
* @return The output
*/
public Out apply(In1 x, In2 y, In3 z);
// TODO: come up with some way to implement a uncurry that won't stack on top of a curry
/**
* Curry the first argument for this function.
*
* @return The function with the first argument curried.
*/
public default Function<In1, BiFunction<In2, In3, Out>> curryFirst() {
return (x) -> (y, z) -> apply(x, y, z);
}
/**
* Curry the third argument for this function.
*
* @return The function with the third argument curried.
*/
public default BiFunction<In1, In2, Function<In3, Out>> curryLast() {
return (x, y) -> (z) -> apply(x, y, z);
}
/**
* Fully curry this function
*
* @return The fully curried function
*/
public default Function<In1, Function<In2, Function<In3, Out>>> fullCurry() {
return (x) -> (y) -> (z) -> apply(x, y, z);
}
/**
* Partially apply the third argument.
*
* @param z The value for the third argument
*
* @return The function w/ the third argument partially applied
*/
public default BiFunction<In1, In2, Out> partialLast(In3 z) {
return (x, y) -> apply(x, y, z);
}
/**
* Partially apply the second argument.
*
* @param y The value for the second argument
*
* @return The function w/ the second argument partially applied
*/
public default BiFunction<In1, In3, Out> partialMiddle(In2 y) {
return (x, z) -> apply(x, y, z);
}
/**
* Partially apply the first argument.
*
* @param x The value for the first argument
*
* @return The function w/ the first argument partially applied
*/
public default BiFunction<In2, In3, Out> partialFirst(In1 x) {
return (y, z) -> apply(x, y, z);
}
/**
* Apply a transform to the output of this function
*
* @param <Out2> The new output type
*
* @param f The mapping function
*
* @return The function with its outputs transformed
*/
public default <Out2> TriFunction<In1, In2, In3, Out2> mapOutput(Function<Out, Out2> f) {
return (x, y, z) -> f.apply(apply(x, y, z));
}
// Possible additions: partial applications which take a Supplier, functions to
// determine one/two of the args based on the others, functions to map one of the args
}
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