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Implement Zipper Eq and Hash and add tests
Signed-off-by: Gábor Lipták <gliptak@gmail.com>
1 parent 5508823 commit ae70d20

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4 files changed

+157
-26
lines changed

4 files changed

+157
-26
lines changed

‎core/src/main/java/fj/Equal.java‎

Lines changed: 16 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -1,19 +1,6 @@
11
package fj;
22

3-
import fj.data.Array;
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import fj.data.Either;
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import fj.data.LazyString;
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import fj.data.List;
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import fj.data.Natural;
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import fj.data.NonEmptyList;
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import fj.data.Option;
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import fj.data.Seq;
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import fj.data.Set;
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import fj.data.Stream;
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import fj.data.Tree;
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import fj.data.TreeMap;
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import fj.data.Validation;
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import fj.data.Writer;
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import fj.data.*;
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import fj.data.hamt.BitSet;
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import fj.data.hlist.HList;
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import fj.data.vector.V2;
@@ -455,6 +442,21 @@ public static <A> Equal<Stream<A>> streamEqual(final Equal<A> ea) {
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});
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}
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/**
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* An equal instance for the {@link Zipper} type.
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*
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* @param ea Equality across the elements of the zipper.
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* @return An equal instance for the {@link Zipper} type.
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*/
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public static <A> Equal<Zipper<A>> zipperEqual(final Equal<A> ea) {
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Equal<Stream<A>> se = Equal.streamEqual(ea);
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return equalDef((a1, a2) ->
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se.eq(a1.lefts(), a2.lefts()) &&
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ea.eq(a1.focus(), a2.focus()) &&
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se.eq(a1.rights(), a2.rights())
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);
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}
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/**
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* An equal instance for the {@link Array} type.
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*

‎core/src/main/java/fj/Hash.java‎

Lines changed: 20 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -262,6 +262,26 @@ public static <A> Hash<Array<A>> arrayHash(final Hash<A> ha) {
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});
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}
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/**
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* A hash instance for the {@link Zipper} type.
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*
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* @param ha A hash for the elements of the zipper.
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* @return A hash instance for the {@link Zipper} type.
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*/
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public static <A> Hash<Zipper<A>> zipperHash(final Hash<A> ha) {
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Hash<Stream<A>> sh = streamHash(ha);
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return hash(as -> {
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final int p = 419;
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int r = 239;
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r = p * r + sh.hash(as.lefts());
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r = p * r + ha.hash(as.focus());
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r = p * r + sh.hash(as.rights());
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return r;
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});
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}
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/**
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* A hash instance for the {@link Tree} type.
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*

‎core/src/main/java/fj/data/Zipper.java‎

Lines changed: 11 additions & 12 deletions
Original file line numberDiff line numberDiff line change
@@ -1,17 +1,6 @@
11
package fj.data;
22

3-
import fj.Equal;
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import fj.F;
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import fj.F2;
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import fj.F2Functions;
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import fj.F3;
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import fj.Function;
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import fj.Ord;
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import fj.P;
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import fj.P1;
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import fj.P2;
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import fj.P3;
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import fj.Show;
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import fj.*;
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import fj.function.Integers;
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import java.util.Iterator;
@@ -106,6 +95,16 @@ public static <A> Ord<Zipper<A>> ord(final Ord<A> o) {
10695
return Ord.p3Ord(so, o, so).contramap(Zipper.p_());
10796
}
10897

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@Override
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public final boolean equals(Object other) {
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return Equal.equals0(Zipper.class, this, other, () -> Equal.zipperEqual(Equal.anyEqual()));
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}
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@Override
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public final int hashCode() {
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return Hash.zipperHash(Hash.<A>anyHash()).hash(this);
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}
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/**
110109
* An Equal instance for Zippers.
111110
*

‎core/src/test/java/fj/data/ZipperTest.java‎

Lines changed: 110 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,110 @@
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package fj.data;
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import org.junit.Test;
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import static org.hamcrest.core.Is.is;
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import static org.junit.Assert.assertThat;
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public class ZipperTest {
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@Test
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public void testZipper() {
11+
Zipper<Integer> z = Zipper.zipper(Stream.nil(), 0, Stream.range(1, 9));
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assertThat(z.map(i -> i + 13).toStream(), is(Stream.range(13, 22)));
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}
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@Test
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public void testNext() {
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Zipper<Integer> z = Zipper.zipper(Stream.single(1), 2, Stream.single(3));
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z = z.next().some();
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assertThat(z.lefts(), is(Stream.arrayStream(new Integer[]{2, 1})));
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assertThat(z.focus(), is(3));
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assertThat(z.rights(), is(Stream.nil()));
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}
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@Test
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public void testNextNone() {
26+
Zipper<Integer> z = Zipper.zipper(Stream.single(1), 2, Stream.nil());
27+
assertThat(z.next().isNone(), is(true));
28+
}
29+
30+
@Test
31+
public void testCycleNext() {
32+
Zipper<Integer> z = Zipper.zipper(Stream.single(1), 2, Stream.single(3));
33+
assertThat(z.cycleNext(), is(z.next().some()));
34+
}
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36+
@Test
37+
public void testCycleNextLast() {
38+
Zipper<Integer> z = Zipper.zipper(Stream.single(1), 2, Stream.nil());
39+
z = z.cycleNext();
40+
assertThat(z.lefts(), is(Stream.nil()));
41+
assertThat(z.focus(), is(1));
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assertThat(z.rights(), is(Stream.single(2)));
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}
44+
45+
@Test
46+
public void testPrevious() {
47+
Zipper<Integer> z = Zipper.zipper(Stream.single(1), 2, Stream.single(3));
48+
z = z.previous().some();
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assertThat(z.lefts(), is(Stream.nil()));
50+
assertThat(z.focus(), is(1));
51+
assertThat(z.rights(), is(Stream.arrayStream(new Integer[]{2, 3})));
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}
53+
54+
@Test
55+
public void testPreviousNone() {
56+
Zipper<Integer> z = Zipper.zipper(Stream.nil(), 2, Stream.single(3));
57+
assertThat(z.previous().isNone(), is(true));
58+
}
59+
60+
@Test
61+
public void testCyclePrevious() {
62+
Zipper<Integer> z = Zipper.zipper(Stream.single(1), 2, Stream.single(3));
63+
assertThat(z.cyclePrevious(), is(z.previous().some()));
64+
}
65+
66+
@Test
67+
public void testCyclePreviousFirst() {
68+
Zipper<Integer> z = Zipper.zipper(Stream.nil(), 1, Stream.single(2));
69+
z = z.cyclePrevious();
70+
assertThat(z.lefts(), is(Stream.single(1)));
71+
assertThat(z.focus(), is(2));
72+
assertThat(z.rights(), is(Stream.nil()));
73+
}
74+
75+
@Test
76+
public void testInsertLeft() {
77+
Zipper<Integer> z = Zipper.single(2);
78+
z = z.insertLeft(1);
79+
assertThat(z.lefts(), is(Stream.nil()));
80+
assertThat(z.focus(), is(1));
81+
assertThat(z.rights(), is(Stream.single(2)));
82+
}
83+
84+
@Test
85+
public void testInsertRight() {
86+
Zipper<Integer> z = Zipper.single(2);
87+
z = z.insertRight(3);
88+
assertThat(z.lefts(), is(Stream.single(2)));
89+
assertThat(z.focus(), is(3));
90+
assertThat(z.rights(), is(Stream.nil()));
91+
}
92+
93+
@Test
94+
public void testDeleteOthers() {
95+
Zipper<Integer> z = Zipper.zipper(Stream.single(1), 2, Stream.single(3));
96+
z = z.deleteOthers();
97+
assertThat(z.lefts(), is(Stream.nil()));
98+
assertThat(z.focus(), is(2));
99+
assertThat(z.rights(), is(Stream.nil()));
100+
}
101+
102+
@Test
103+
public void testFind() {
104+
Zipper<Integer> z = Zipper.zipper(Stream.nil(), 0, Stream.range(1));
105+
z = z.find(i -> i == 4).some();
106+
assertThat(z.lefts(), is(Stream.arrayStream(new Integer[]{3, 2, 1, 0})));
107+
assertThat(z.focus(), is(4));
108+
assertThat(z.rights().take(3), is(Stream.range(5, 8)));
109+
}
110+
}

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