add voidRight in ExtraFunctor

CHANGELOG.md

@@ -5,6 +5,10 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic versioning](http://semver.org/).
 
+## [unreleased]
+
+- add `voidRight` in `ExtraFunctor`
+
 ## [3.0.1] - 2023-09-28
 
 - fix `Traversable` instance for `ListL`

src/Typeclass/Extra/ExtraFunctor.php

@@ -0,0 +1,43 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Marcosh\LamPHPda\Typeclass\Extra;
+
+use Marcosh\LamPHPda\Brand\Brand;
+use Marcosh\LamPHPda\HK\HK1;
+use Marcosh\LamPHPda\Typeclass\Functor;
+
+/**
+ * @template F of Brand
+ *
+ * @psalm-immutable
+ */
+final class ExtraFunctor
+{
+    /** @var Functor<F> */
+    private Functor $functor;
+
+    /**
+     * @param Functor<F> $functor
+     */
+    public function __construct(Functor $functor)
+    {
+        $this->functor = $functor;
+    }
+
+    /**
+     * @template A
+     * @template B
+     * @param A $a
+     * @param HK1<F, B> $hk
+     * @return HK1<F, A>
+     */
+    public function voidRight($a, HK1 $hk): HK1
+    {
+        return $this->functor->map(
+            static fn ($_) => $a,
+            $hk
+        );
+    }
+}