add method to do a 1-1 map to another type

Innmind · Dec 15, 2019 · 4471cd8 · 4471cd8
1 parent 2e42f35
commit 4471cd8
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Showing 4 changed files with 60 additions and 0 deletions.
diff --git a/src/Sequence.php b/src/Sequence.php
@@ -360,6 +360,25 @@ public function map(callable $function): self
         return $self;
     }
 
+    /**
+     * Create a new Sequence with the exact same number of elements but with a
+     * new type transformed via the given function
+     *
+     * @template S
+     *
+     * @param callable(T): S $map
+     *
+     * @return self<S>
+     */
+    public function mapTo(string $type, callable $map): self
+    {
+        /** @psalm-suppress MixedArgument */
+        return $this->toSequenceOf(
+            $type,
+            static fn($value): \Generator => yield $map($value),
+        );
+    }
+
     /**
      * Pad the sequence to a defined size with the given element
      *

diff --git a/src/Set.php b/src/Set.php
@@ -315,6 +315,25 @@ public function map(callable $function): self
         return $self;
     }
 
+    /**
+     * Create a new Set with the exact same number of elements but with a
+     * new type transformed via the given function
+     *
+     * @template S
+     *
+     * @param callable(T): S $map
+     *
+     * @return self<S>
+     */
+    public function mapTo(string $type, callable $map): self
+    {
+        /** @psalm-suppress MixedArgument */
+        return $this->toSetOf(
+            $type,
+            static fn($value): \Generator => yield $map($value),
+        );
+    }
+
     /**
      * Return a sequence of 2 sets partitioned according to the given predicate
      *

diff --git a/tests/SequenceTest.php b/tests/SequenceTest.php
@@ -411,6 +411,17 @@ public function testMap()
         $this->assertSame([1, 4, 9, 16], unwrap($b));
     }
 
+    public function testMapTo()
+    {
+        $a = Sequence::ints(1, 2, 3, 4);
+        $b = $a->mapTo('string', fn($i) => (string) $i);
+
+        $this->assertInstanceOf(Sequence::class, $b);
+        $this->assertNotSame($a, $b);
+        $this->assertSame('string', $b->type());
+        $this->assertSame(['1', '2', '3', '4'], unwrap($b));
+    }
+
     public function testThrowWhenTryingToModifyValueTypeInMap()
     {
         $this->expectException(\TypeError::class);

diff --git a/tests/SetTest.php b/tests/SetTest.php
@@ -326,6 +326,17 @@ public function testMap()
         $this->assertSame([1, 4, 9, 16], unwrap($s2));
     }
 
+    public function testMapTo()
+    {
+        $a = Set::ints(1, 2, 3, 4);
+        $b = $a->mapTo('string', fn($i) => (string) $i);
+
+        $this->assertInstanceOf(Set::class, $b);
+        $this->assertNotSame($a, $b);
+        $this->assertSame('string', $b->type());
+        $this->assertSame(['1', '2', '3', '4'], unwrap($b));
+    }
+
     public function testThrowWhenTryingToModifyValueTypeInMap()
     {
         $this->expectException(\TypeError::class);