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Adding #project for coproducts
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8 files changed

+109
-1
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‎src/main/java/com/jnape/palatable/lambda/adt/coproduct/CoProduct2.java

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@@ -1,11 +1,15 @@
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package com.jnape.palatable.lambda.adt.coproduct;
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import com.jnape.palatable.lambda.adt.hlist.Tuple2;
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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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import java.util.Objects;
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import java.util.Optional;
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import java.util.function.Function;
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import static com.jnape.palatable.lambda.adt.hlist.HList.tuple;
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/**
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* A generalization of the coproduct of two types <code>A</code> and <code>B</code>. Coproducts represent the disjoint
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* union of two or more distinct types, and provides an interface for specifying morphisms from those types to a common
@@ -58,6 +62,17 @@ default <C> CoProduct3<A, B, C> diverge() {
5862
return match(CoProduct3::a, CoProduct3::b);
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}
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/**
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* Project this coproduct onto a tuple, such that the slot in the tuple that corresponds to this coproduct's value
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* is present, while the other slots are absent.
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*
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* @return a tuple of the coproduct projection
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*/
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default Tuple2<Optional<A>, Optional<B>> project() {
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return match(a -> tuple(Optional.of(a), Optional.empty()),
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b -> tuple(Optional.empty(), Optional.of(b)));
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}
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@Override
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default <C> CoProduct2<A, C> fmap(Function<? super B, ? extends C> fn) {
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return biMapR(fn);

‎src/main/java/com/jnape/palatable/lambda/adt/coproduct/CoProduct3.java

Lines changed: 16 additions & 1 deletion
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@@ -1,11 +1,15 @@
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package com.jnape.palatable.lambda.adt.coproduct;
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import com.jnape.palatable.lambda.adt.hlist.Tuple3;
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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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import java.util.Objects;
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import java.util.Optional;
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import java.util.function.Function;
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import static com.jnape.palatable.lambda.adt.hlist.HList.tuple;
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/**
1014
* A generalization of the coproduct of three types <code>A</code>, <code>B</code>, and <code>C</code>.
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*
@@ -30,7 +34,6 @@ public interface CoProduct3<A, B, C> extends Functor<C>, Bifunctor<B, C> {
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<R> R match(Function<? super A, ? extends R> aFn, Function<? super B, ? extends R> bFn,
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Function<? super C, ? extends R> cFn);
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33-
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/**
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* Diverge this coproduct by introducing another possible type that it could represent.
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*
@@ -42,6 +45,18 @@ default <D> CoProduct4<A, B, C, D> diverge() {
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return match(CoProduct4::a, CoProduct4::b, CoProduct4::c);
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}
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/**
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* Project this coproduct onto a tuple.
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*
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* @return a tuple of the coproduct projection
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* @see CoProduct2#project()
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*/
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default Tuple3<Optional<A>, Optional<B>, Optional<C>> project() {
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return match(a -> tuple(Optional.of(a), Optional.empty(), Optional.empty()),
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b -> tuple(Optional.empty(), Optional.of(b), Optional.empty()),
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c -> tuple(Optional.empty(), Optional.empty(), Optional.of(c)));
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}
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@Override
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default <D> CoProduct3<A, B, D> fmap(Function<? super C, ? extends D> fn) {
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return biMapR(fn);

‎src/main/java/com/jnape/palatable/lambda/adt/coproduct/CoProduct4.java

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package com.jnape.palatable.lambda.adt.coproduct;
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import com.jnape.palatable.lambda.adt.hlist.Tuple4;
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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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import java.util.Objects;
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import java.util.Optional;
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import java.util.function.Function;
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import static com.jnape.palatable.lambda.adt.hlist.HList.tuple;
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913
/**
1014
* A generalization of the coproduct of four types <code>A</code>, <code>B</code>, <code>C</code>, and <code>D</code>.
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*
@@ -45,6 +49,19 @@ default <E> CoProduct5<A, B, C, D, E> diverge() {
4549
return match(CoProduct5::a, CoProduct5::b, CoProduct5::c, CoProduct5::d);
4650
}
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/**
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* Project this coproduct onto a tuple.
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*
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* @return a tuple of the coproduct projection
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* @see CoProduct2#project()
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*/
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default Tuple4<Optional<A>, Optional<B>, Optional<C>, Optional<D>> project() {
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return match(a -> tuple(Optional.of(a), Optional.empty(), Optional.empty(), Optional.empty()),
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b -> tuple(Optional.empty(), Optional.of(b), Optional.empty(), Optional.empty()),
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c -> tuple(Optional.empty(), Optional.empty(), Optional.of(c), Optional.empty()),
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d -> tuple(Optional.empty(), Optional.empty(), Optional.empty(), Optional.of(d)));
63+
}
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4865
@Override
4966
default <E> CoProduct4<A, B, C, E> fmap(Function<? super D, ? extends E> fn) {
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return biMapR(fn);

‎src/main/java/com/jnape/palatable/lambda/adt/coproduct/CoProduct5.java

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package com.jnape.palatable.lambda.adt.coproduct;
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import com.jnape.palatable.lambda.adt.hlist.Tuple5;
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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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import java.util.Objects;
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import java.util.Optional;
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import java.util.function.Function;
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import static com.jnape.palatable.lambda.adt.hlist.HList.tuple;
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/**
1014
* A generalization of the coproduct of five types <code>A</code>, <code>B</code>, <code>C</code>, <code>D</code>, and
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* <code>E</code>.
@@ -38,6 +42,20 @@ <R> R match(Function<? super A, ? extends R> aFn,
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Function<? super D, ? extends R> dFn,
3943
Function<? super E, ? extends R> eFn);
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/**
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* Project this coproduct onto a tuple.
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*
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* @return a tuple of the coproduct projection
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* @see CoProduct2#project()
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*/
51+
default Tuple5<Optional<A>, Optional<B>, Optional<C>, Optional<D>, Optional<E>> project() {
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return match(a -> tuple(Optional.of(a), Optional.empty(), Optional.empty(), Optional.empty(), Optional.empty()),
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b -> tuple(Optional.empty(), Optional.of(b), Optional.empty(), Optional.empty(), Optional.empty()),
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c -> tuple(Optional.empty(), Optional.empty(), Optional.of(c), Optional.empty(), Optional.empty()),
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d -> tuple(Optional.empty(), Optional.empty(), Optional.empty(), Optional.of(d), Optional.empty()),
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e -> tuple(Optional.empty(), Optional.empty(), Optional.empty(), Optional.empty(), Optional.of(e)));
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}
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@Override
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default <F> CoProduct5<A, B, C, D, F> fmap(Function<? super E, ? extends F> fn) {
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return biMapR(fn);

‎src/test/java/com/jnape/palatable/lambda/adt/coproduct/CoProduct2Test.java

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@@ -3,8 +3,11 @@
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import org.junit.Before;
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import org.junit.Test;
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import java.util.Optional;
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import static com.jnape.palatable.lambda.adt.coproduct.CoProduct2.a;
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import static com.jnape.palatable.lambda.adt.coproduct.CoProduct2.b;
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import static com.jnape.palatable.lambda.adt.hlist.HList.tuple;
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import static com.jnape.palatable.lambda.functions.builtin.fn1.Id.id;
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import static org.junit.Assert.assertEquals;
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@@ -31,6 +34,12 @@ public void diverge() {
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assertEquals(CoProduct3.b(true), b.diverge());
3235
}
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37+
@Test
38+
public void project() {
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assertEquals(tuple(Optional.of(1), Optional.empty()), CoProduct2.a(1).project());
40+
assertEquals(tuple(Optional.empty(), Optional.of("b")), CoProduct2.b("b").project());
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}
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3443
@Test
3544
public void functorProperties() {
3645
assertEquals(a, a.fmap(bool -> !bool));

‎src/test/java/com/jnape/palatable/lambda/adt/coproduct/CoProduct3Test.java

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@@ -3,9 +3,12 @@
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import org.junit.Before;
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import org.junit.Test;
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import java.util.Optional;
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import static com.jnape.palatable.lambda.adt.coproduct.CoProduct3.a;
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import static com.jnape.palatable.lambda.adt.coproduct.CoProduct3.b;
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import static com.jnape.palatable.lambda.adt.coproduct.CoProduct3.c;
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import static com.jnape.palatable.lambda.adt.hlist.HList.tuple;
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import static com.jnape.palatable.lambda.functions.builtin.fn1.Id.id;
1013
import static org.junit.Assert.assertEquals;
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@@ -36,6 +39,13 @@ public void diverge() {
3639
assertEquals(CoProduct4.c(true), c.diverge());
3740
}
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42+
@Test
43+
public void project() {
44+
assertEquals(tuple(Optional.of(1), Optional.empty(), Optional.empty()), CoProduct3.a(1).project());
45+
assertEquals(tuple(Optional.empty(), Optional.of("b"), Optional.empty()), CoProduct3.b("b").project());
46+
assertEquals(tuple(Optional.empty(), Optional.empty(), Optional.of('c')), CoProduct3.c('c').project());
47+
}
48+
3949
@Test
4050
public void functorProperties() {
4151
assertEquals(a, a.fmap(bool -> !bool));

‎src/test/java/com/jnape/palatable/lambda/adt/coproduct/CoProduct4Test.java

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import org.junit.Before;
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import org.junit.Test;
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import java.util.Optional;
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import static com.jnape.palatable.lambda.adt.coproduct.CoProduct4.a;
79
import static com.jnape.palatable.lambda.adt.coproduct.CoProduct4.b;
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import static com.jnape.palatable.lambda.adt.coproduct.CoProduct4.c;
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import static com.jnape.palatable.lambda.adt.coproduct.CoProduct4.d;
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import static com.jnape.palatable.lambda.adt.hlist.HList.tuple;
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import static com.jnape.palatable.lambda.functions.builtin.fn1.Id.id;
1114
import static org.junit.Assert.assertEquals;
1215

@@ -41,6 +44,14 @@ public void diverge() {
4144
assertEquals(CoProduct5.d(4D), d.diverge());
4245
}
4346

47+
@Test
48+
public void project() {
49+
assertEquals(tuple(Optional.of(1), Optional.empty(), Optional.empty(), Optional.empty()), CoProduct4.a(1).project());
50+
assertEquals(tuple(Optional.empty(), Optional.of("b"), Optional.empty(), Optional.empty()), CoProduct4.b("b").project());
51+
assertEquals(tuple(Optional.empty(), Optional.empty(), Optional.of('c'), Optional.empty()), CoProduct4.c('c').project());
52+
assertEquals(tuple(Optional.empty(), Optional.empty(), Optional.empty(), Optional.of(4L)), CoProduct4.d(4L).project());
53+
}
54+
4455
@Test
4556
public void functorProperties() {
4657
assertEquals(a, a.fmap(d -> -d));

‎src/test/java/com/jnape/palatable/lambda/adt/coproduct/CoProduct5Test.java

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import org.junit.Before;
44
import org.junit.Test;
55

6+
import java.util.Optional;
7+
68
import static com.jnape.palatable.lambda.adt.coproduct.CoProduct5.a;
79
import static com.jnape.palatable.lambda.adt.coproduct.CoProduct5.b;
810
import static com.jnape.palatable.lambda.adt.coproduct.CoProduct5.c;
911
import static com.jnape.palatable.lambda.adt.coproduct.CoProduct5.d;
1012
import static com.jnape.palatable.lambda.adt.coproduct.CoProduct5.e;
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import static com.jnape.palatable.lambda.adt.hlist.HList.tuple;
1114
import static com.jnape.palatable.lambda.functions.builtin.fn1.Id.id;
1215
import static org.junit.Assert.assertEquals;
1316

@@ -37,6 +40,16 @@ public void match() {
3740
assertEquals('z', e.match(id(), id(), id(), id(), id()));
3841
}
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43+
@Test
44+
public void project() {
45+
assertEquals(tuple(Optional.of(1), Optional.empty(), Optional.empty(), Optional.empty(), Optional.empty()), CoProduct5.a(1).project());
46+
assertEquals(tuple(Optional.empty(), Optional.of("b"), Optional.empty(), Optional.empty(), Optional.empty()), CoProduct5.b("b").project());
47+
assertEquals(tuple(Optional.empty(), Optional.empty(), Optional.of('c'), Optional.empty(), Optional.empty()), CoProduct5.c('c').project());
48+
assertEquals(tuple(Optional.empty(), Optional.empty(), Optional.empty(), Optional.of(4L), Optional.empty()), CoProduct5.d(4L).project());
49+
assertEquals(tuple(Optional.empty(), Optional.empty(), Optional.empty(), Optional.empty(), Optional.of(false)), CoProduct5.e(false).project());
50+
}
51+
52+
4053
@Test
4154
public void functorProperties() {
4255
assertEquals(a, a.fmap(Character::toUpperCase));

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