Tupler2: create a tuple from 2 inputs

jnape · jnape · commit 29fe86e8e67b · 2014-03-09T19:57:16.000-04:00
diff --git a/src/main/java/com/jnape/palatable/lambda/builtin/dyadic/Tupler2.java b/src/main/java/com/jnape/palatable/lambda/builtin/dyadic/Tupler2.java
@@ -0,0 +1,18 @@
+package com.jnape.palatable.lambda.builtin.dyadic;
+
+import com.jnape.palatable.lambda.DyadicFunction;
+import com.jnape.palatable.lambda.tuples.Tuple2;
+
+import static com.jnape.palatable.lambda.tuples.Tuple2.tuple;
+
+public final class Tupler2<A, B> extends DyadicFunction<A, B, Tuple2<A, B>> {
+
+    @Override
+    public final Tuple2<A, B> apply(A a, B b) {
+        return tuple(a, b);
+    }
+
+    public static <A, B> Tupler2<A, B> tupler() {
+        return new Tupler2<A, B>();
+    }
+}
diff --git a/src/main/java/com/jnape/palatable/lambda/builtin/monadic/Identity.java b/src/main/java/com/jnape/palatable/lambda/builtin/monadic/Identity.java
@@ -2,10 +2,10 @@
 
 import com.jnape.palatable.lambda.MonadicFunction;
 
-public class Identity<A> extends MonadicFunction<A, A> {
+public final class Identity<A> extends MonadicFunction<A, A> {
 
     @Override
-    public A apply(A a) {
+    public final A apply(A a) {
         return a;
     }
 
diff --git a/src/main/java/com/jnape/palatable/lambda/functions/Zip.java b/src/main/java/com/jnape/palatable/lambda/functions/Zip.java
@@ -2,21 +2,16 @@
 
 import com.jnape.palatable.lambda.DyadicFunction;
 import com.jnape.palatable.lambda.MonadicFunction;
+import com.jnape.palatable.lambda.builtin.dyadic.Tupler2;
 import com.jnape.palatable.lambda.tuples.Tuple2;
 
 import static com.jnape.palatable.lambda.functions.ZipWith.zipWith;
-import static com.jnape.palatable.lambda.tuples.Tuple2.tuple;
 
 public final class Zip<A, B> extends DyadicFunction<Iterable<A>, Iterable<B>, Iterable<Tuple2<A, B>>> {
 
     @Override
     public final Iterable<Tuple2<A, B>> apply(final Iterable<A> as, final Iterable<B> bs) {
-        return zipWith(new DyadicFunction<A, B, Tuple2<A, B>>() {
-            @Override
-            public Tuple2<A, B> apply(A a, B b) {
-                return tuple(a, b);
-            }
-        }, as, bs);
+        return zipWith(Tupler2.<A, B>tupler(), as, bs);
     }
 
     public static <A, B> DyadicFunction<Iterable<A>, Iterable<B>, Iterable<Tuple2<A, B>>> zip() {
diff --git a/src/test/java/com/jnape/palatable/lambda/builtin/dyadic/Tupler2Test.java b/src/test/java/com/jnape/palatable/lambda/builtin/dyadic/Tupler2Test.java
@@ -0,0 +1,16 @@
+package com.jnape.palatable.lambda.builtin.dyadic;
+
+import org.junit.Test;
+
+import static com.jnape.palatable.lambda.tuples.Tuple2.tuple;
+import static org.hamcrest.core.Is.is;
+import static org.junit.Assert.assertThat;
+
+public class Tupler2Test {
+
+    @Test
+    public void createsTupleOfTwoThings() {
+        Tupler2<String, Integer> tupler = new Tupler2<String, Integer>();
+        assertThat(tupler.apply("a", 1), is(tuple("a", 1)));
+    }
+}

Original file line number	Diff line number	Diff line change
`@@ -2,10 +2,10 @@`
`2`	`2`
`3`	`3`	`import com.jnape.palatable.lambda.MonadicFunction;`
`4`	`4`
`5`		`-public class Identity<A> extends MonadicFunction<A, A> {`
	`5`	`+public final class Identity<A> extends MonadicFunction<A, A> {`
`6`	`6`
`7`	`7`	`@Override`
`8`		`- public A apply(A a) {`
	`8`	`+ public final A apply(A a) {`
`9`	`9`	`return a;`
`10`	`10`	`}`
`11`	`11`