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Moving semigroups and monoids under fn2 for better discoverability; various renaming.
Adding Monoid/Semigroup factory specializations of Fn3, adding Fn4 for Bi-specializations, and condensing dual semigroup and monoid function types into single classes with specific static factory methods. monoid/semigroups include: - LeftAll - RightAll - LeftAny - RightAny - Concat - Collapse - Merge - Present - PutAll
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‎src/main/java/com/jnape/palatable/lambda/adt/hlist/Tuple2.java

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package com.jnape.palatable.lambda.adt.hlist;
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import com.jnape.palatable.lambda.adt.hlist.HList.HCons;
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import com.jnape.palatable.lambda.monoid.Monoid;
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import com.jnape.palatable.lambda.functor.Bifunctor;
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import com.jnape.palatable.lambda.functor.Functor;
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@@ -90,6 +91,13 @@ public <_1Prime, _2Prime> Tuple2<_1Prime, _2Prime> biMap(Function<? super _1, ?
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return new Tuple2<>(lFn.apply(_1()), tail().fmap(rFn));
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}
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public static <_1, _2> Monoid<Tuple2<_1, _2>> monoid(Monoid<_1> _1Monoid, Monoid<_2> _2Monoid) {
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return Monoid.monoid(
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(x, y) -> x.biMap(_1Monoid.flip().apply(y._1()),
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_2Monoid.flip().apply(y._2())),
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tuple(_1Monoid.identity(), _2Monoid.identity()));
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}
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/**
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* Static factory method for creating <code>Tuple2</code>s from {@link java.util.Map.Entry}s.
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*
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public static <K, V> Tuple2<K, V> fromEntry(Map.Entry<K, V> entry) {
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return new Tuple2<>(entry.getKey(), singletonHList(entry.getValue()));
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}
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}

‎src/main/java/com/jnape/palatable/lambda/functions/Fn2.java

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* @param <B> The second argument type
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* @param <C> The return type
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* @see Fn1
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* @see com.jnape.palatable.lambda.functions.builtin.fn2.Partial2
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*/
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@FunctionalInterface
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public interface Fn2<A, B, C> extends Fn1<A, Fn1<B, C>> {

‎src/main/java/com/jnape/palatable/lambda/functions/Fn3.java

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* @param <C> The third argument type
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* @param <D> The return type
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* @see Fn2
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* @see com.jnape.palatable.lambda.functions.builtin.fn2.Partial3
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*/
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@FunctionalInterface
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public interface Fn3<A, B, C, D> extends Fn2<A, B, Fn1<C, D>> {

‎src/main/java/com/jnape/palatable/lambda/functions/Fn4.java

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package com.jnape.palatable.lambda.functions;
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import com.jnape.palatable.lambda.adt.hlist.Tuple2;
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/**
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* A function taking four arguments. Defined in terms of <code>Fn3</code>, so similarly auto-curried.
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*
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* @param <A> The first argument type
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* @param <B> The second argument type
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* @param <C> The third argument type
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* @param <D> The fourth argument type
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* @param <E> The return type
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* @see Fn3
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*/
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@FunctionalInterface
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public interface Fn4<A, B, C, D, E> extends Fn3<A, B, C, Fn1<D, E>> {
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/**
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* Invoke this function with the given arguments.
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*
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* @param a the first argument
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* @param b the second argument
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* @param c the third argument
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* @param d the fourth argument
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* @return the result of the function application
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*/
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E apply(A a, B b, C c, D d);
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/**
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* Partially apply this function by taking its first argument.
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*
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* @param a the first argument
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* @return an Fn3 that takes the second, third, and fourth argument and returns the result
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*/
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@Override
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default Fn3<B, C, D, E> apply(A a) {
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return (b, c, d) -> apply(a, b, c, d);
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}
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/**
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* Partially apply this function by taking its first two arguments.
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*
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* @param a the first argument
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* @param b the second argument
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* @return an Fn2 that takes the third and fourth arguments and returns the result
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*/
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@Override
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default Fn2<C, D, E> apply(A a, B b) {
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return (c, d) -> apply(a, b, c, d);
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}
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/**
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* Partially apply this function by taking its first three arguments.
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*
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* @param a the first argument
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* @param b the second argument
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* @param c the third argument
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* @return an Fn1 that takes the fourth argument and returns the result
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*/
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@Override
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default Fn1<D, E> apply(A a, B b, C c) {
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return (d) -> apply(a, b, c, d);
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}
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/**
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* Flip the order of the first two arguments.
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*
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* @return an Fn3 that takes the first and second arguments in reversed order
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*/
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@Override
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default Fn4<B, A, C, D, E> flip() {
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return (b, a, c, d) -> apply(a, b, c, d);
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}
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/**
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* Returns an <code>Fn3</code> that takes the first two arguments as a <code>Tuple2&lt;A, B&gt;</code> and the third
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* and fourth arguments.
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*
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* @return an Fn3 taking a Tuple2 and the third and fourth arguments
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*/
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@Override
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default Fn3<Tuple2<A, B>, C, D, E> uncurry() {
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return (ab, c, d) -> apply(ab._1(), ab._2(), c, d);
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}
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}

‎src/main/java/com/jnape/palatable/lambda/functions/specialized/BiMonoidFactory.java

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package com.jnape.palatable.lambda.functions.specialized;
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import com.jnape.palatable.lambda.adt.hlist.Tuple2;
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import com.jnape.palatable.lambda.monoid.Monoid;
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@FunctionalInterface
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public interface BiMonoidFactory<A, B, C> extends BiSemigroupFactory<A, B, C> {
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@Override
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default MonoidFactory<B, C> apply(A a) {
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return b -> apply(a, b);
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}
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@Override
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Monoid<C> apply(A a, B b);
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@Override
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default BiMonoidFactory<B, A, C> flip() {
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return (b, a) -> apply(a, b);
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}
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@Override
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default MonoidFactory<Tuple2<A, B>, C> uncurry() {
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return ab -> apply(ab._1()).apply(ab._2());
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}
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}

‎src/main/java/com/jnape/palatable/lambda/functions/specialized/BiSemigroupFactory.java

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package com.jnape.palatable.lambda.functions.specialized;
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import com.jnape.palatable.lambda.adt.hlist.Tuple2;
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import com.jnape.palatable.lambda.functions.Fn4;
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import com.jnape.palatable.lambda.semigroup.Semigroup;
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@FunctionalInterface
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public interface BiSemigroupFactory<A, B, C> extends Fn4<A, B, C, C, C> {
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@Override
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Semigroup<C> apply(A a, B b);
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@Override
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default SemigroupFactory<B, C> apply(A a) {
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return b -> apply(a, b);
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}
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@Override
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default BiSemigroupFactory<B, A, C> flip() {
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return (b, a) -> apply(a, b);
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}
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@Override
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default SemigroupFactory<Tuple2<A, B>, C> uncurry() {
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return ab -> apply(ab._1(), ab._2());
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}
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@Override
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default C apply(A a, B b, C c, C d) {
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return apply(a).apply(b).apply(c, d);
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}
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}

‎src/main/java/com/jnape/palatable/lambda/functions/specialized/MonoidFactory.java

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package com.jnape.palatable.lambda.functions.specialized;
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import com.jnape.palatable.lambda.monoid.Monoid;
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public interface MonoidFactory<A, B> extends SemigroupFactory<A, B> {
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@Override
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default B apply(A a, B b, B c) {
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return apply(a).apply(b, c);
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}
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@Override
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Monoid<B> apply(A a);
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}

‎src/main/java/com/jnape/palatable/lambda/functions/specialized/SemigroupFactory.java

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package com.jnape.palatable.lambda.functions.specialized;
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import com.jnape.palatable.lambda.functions.Fn3;
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import com.jnape.palatable.lambda.semigroup.Semigroup;
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@FunctionalInterface
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public interface SemigroupFactory<A, B> extends Fn3<A, B, B, B> {
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@Override
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Semigroup<B> apply(A a);
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@Override
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default B apply(A a, B b, B c) {
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return apply(a).apply(b, c);
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}
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}

‎src/main/java/com/jnape/palatable/lambda/monoid/Monoid.java

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import com.jnape.palatable.lambda.semigroup.Semigroup;
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import java.util.function.Function;
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import java.util.function.Supplier;
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import static com.jnape.palatable.lambda.functions.builtin.fn2.Map.map;
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@@ -84,4 +85,18 @@ public A apply(A x, A y) {
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}
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};
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}
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static <A> Monoid<A> monoid(Semigroup<A> semigroup, Supplier<A> identitySupplier) {
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return new Monoid<A>() {
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@Override
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public A identity() {
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return identitySupplier.get();
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}
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@Override
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public A apply(A x, A y) {
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return semigroup.apply(x, y);
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}
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};
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}
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}

‎src/main/java/com/jnape/palatable/lambda/monoid/builtin/Collapse.java

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package com.jnape.palatable.lambda.monoid.builtin;
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import com.jnape.palatable.lambda.adt.hlist.Tuple2;
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import com.jnape.palatable.lambda.functions.Fn1;
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import com.jnape.palatable.lambda.functions.specialized.BiMonoidFactory;
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import com.jnape.palatable.lambda.functions.specialized.MonoidFactory;
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import com.jnape.palatable.lambda.monoid.Monoid;
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import com.jnape.palatable.lambda.semigroup.Semigroup;
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import static com.jnape.palatable.lambda.adt.hlist.HList.tuple;
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/**
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* A {@link Monoid} instance formed by a <code>{@link Tuple2}&lt;_1, _2&gt;</code> and monoids over <code>_1</code> and
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* <code>_2</code>. Successively collapses multiple {@link Tuple2}s into a single {@link Tuple2} by collapsing the
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* values of each slot under the provided monoid instance.
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* <p>
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* For the {@link Semigroup}, see {@link com.jnape.palatable.lambda.semigroup.builtin.Collapse}.
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*
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* @param <_1> the first slot parameter type
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* @param <_2> the second slot parameter type
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* @see Monoid
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* @see Tuple2
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*/
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public final class Collapse<_1, _2> implements BiMonoidFactory<Monoid<_1>, Monoid<_2>, Tuple2<_1, _2>> {
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private static final Collapse INSTANCE = new Collapse();
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private Collapse() {
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}
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@Override
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public Monoid<Tuple2<_1, _2>> apply(Monoid<_1> _1Monoid, Monoid<_2> _2Monoid) {
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Semigroup<Tuple2<_1, _2>> semigroup = com.jnape.palatable.lambda.semigroup.builtin.Collapse.collapse(_1Monoid, _2Monoid);
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return Monoid.<Tuple2<_1, _2>>monoid(semigroup, () -> tuple(_1Monoid.identity(), _2Monoid.identity()));
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}
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@SuppressWarnings("unchecked")
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public static <_1, _2> Collapse<_1, _2> collapse() {
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return INSTANCE;
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}
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public static <_1, _2> MonoidFactory<Monoid<_2>, Tuple2<_1, _2>> collapse(Monoid<_1> _1Monoid) {
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return Collapse.<_1, _2>collapse().apply(_1Monoid);
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}
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public static <_1, _2> Monoid<Tuple2<_1, _2>> collapse(Monoid<_1> _1Monoid, Monoid<_2> _2Monoid) {
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return Collapse.<_1, _2>collapse(_1Monoid).apply(_2Monoid);
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}
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public static <_1, _2> Fn1<Tuple2<_1, _2>, Tuple2<_1, _2>> collapse(Monoid<_1> _1Monoid, Monoid<_2> _2Monoid,
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Tuple2<_1, _2> x) {
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return collapse(_1Monoid, _2Monoid).apply(x);
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}
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public static <_1, _2> Tuple2<_1, _2> collapse(Monoid<_1> _1Monoid, Monoid<_2> _2Monoid, Tuple2<_1, _2> x,
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Tuple2<_1, _2> y) {
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return collapse(_1Monoid, _2Monoid, x).apply(y);
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}
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}

‎src/main/java/com/jnape/palatable/lambda/monoid/builtin/Concat.java

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package com.jnape.palatable.lambda.monoid.builtin;
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import com.jnape.palatable.lambda.functions.Fn1;
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import com.jnape.palatable.lambda.functions.specialized.MonoidFactory;
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import com.jnape.palatable.lambda.monoid.Monoid;
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import com.jnape.palatable.lambda.semigroup.Semigroup;
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import java.util.Collection;
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import java.util.function.Supplier;
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import static com.jnape.palatable.lambda.monoid.Monoid.monoid;
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/**
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* The {@link Monoid} instance formed under concatenation for an arbitrary {@link Collection}. The collection subtype
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* (<code>C</code>) must support {@link Collection#addAll(Collection)}.
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* <p>
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* For the {@link Semigroup}, see {@link com.jnape.palatable.lambda.semigroup.builtin.Concat}.
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*
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* @see Monoid
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*/
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public final class Concat<A, C extends Collection<A>> implements MonoidFactory<Supplier<C>, C> {
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private static final Concat INSTANCE = new Concat();
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private Concat() {
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}
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@Override
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public Monoid<C> apply(Supplier<C> cSupplier) {
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Semigroup<C> semigroup = com.jnape.palatable.lambda.semigroup.builtin.Concat.concat();
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return monoid(semigroup, cSupplier);
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}
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@SuppressWarnings("unchecked")
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public static <A, C extends Collection<A>> Concat<A, C> concat() {
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return INSTANCE;
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}
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public static <A, C extends Collection<A>> Monoid<C> concat(Supplier<C> collectionSupplier) {
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return Concat.<A, C>concat().apply(collectionSupplier);
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}
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public static <A, C extends Collection<A>> Fn1<C, C> concat(Supplier<C> collectionSupplier, C xs) {
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return concat(collectionSupplier).apply(xs);
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}
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public static <A, C extends Collection<A>> C concat(Supplier<C> collectionSupplier, C xs, C ys) {
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return concat(collectionSupplier, xs).apply(ys);
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}
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}

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