Add IdentityTypeResolver and TypeResolvers composite

src/Type/CHANGELOG.md

@@ -5,6 +5,13 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.4.4]
+
+### Added
+
+- Add `IdentityTypeResolver` — a type resolver that resolves to the passed type.
+- Add `TypeResolvers` — a composite for type resolvers.
+
 ## [0.4.3] 2024-08-06
 
 ### Added

src/Type/Visitor/IdentityTypeResolver.php

@@ -0,0 +1,19 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Typhoon\Type\Visitor;
+
+use Typhoon\Type\Type;
+
+/**
+ * @api
+ * @extends DefaultTypeVisitor<Type>
+ */
+final class IdentityTypeResolver extends DefaultTypeVisitor
+{
+    protected function default(Type $type): Type
+    {
+        return $type;
+    }
+}

src/Type/Visitor/TypeResolvers.php

@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Typhoon\Type\Visitor;
+
+use Typhoon\Type\Type;
+use Typhoon\Type\TypeVisitor;
+
+/**
+ * @api
+ * @extends DefaultTypeVisitor<Type>
+ */
+final class TypeResolvers extends DefaultTypeVisitor
+{
+    /**
+     * @param list<TypeVisitor<Type>> $resolvers
+     * @return TypeVisitor<Type>
+     */
+    public static function from(array $resolvers): TypeVisitor
+    {
+        return match (\count($resolvers)) {
+            0 => new IdentityTypeResolver(),
+            1 => $resolvers[0],
+            default => new self($resolvers),
+        };
+    }
+
+    /**
+     * @param non-empty-list<TypeVisitor<Type>> $resolvers
+     */
+    private function __construct(
+        private readonly array $resolvers,
+    ) {}
+
+    protected function default(Type $type): mixed
+    {
+        foreach ($this->resolvers as $resolver) {
+            $type = $type->accept($resolver);
+        }
+
+        return $type;
+    }
+}