Change how to stringify declared classes and such

Currently, the library treats class names, interface names, trait names,
and enumeration names as simple strings, but treating them as particular
values is a better approach.

Signed-off-by: Henrique Moody <henriquemoody@gmail.com>

Author: henriquemoody

README.md

@@ -153,6 +153,9 @@ echo stringify(new RuntimeException()) . PHP_EOL;
 
 echo stringify(new InvalidArgumentException('This is the exception message')) . PHP_EOL;
 // `InvalidArgumentException { "This is the exception message" in file.php:112 }`
+
+echo stringify(Traversable::class) . PHP_EOL;
+// `Traversable`
 ```
 
 To see more examples of how to use the library check the [integration tests](tests/integration).

src/Stringifiers/CompositeStringifier.php

@@ -43,6 +43,7 @@ public static function createDefault(): self
             new ResourceStringifier($quoter),
             new BoolStringifier($quoter),
             new NullStringifier($quoter),
+            new DeclaredStringifier($quoter),
             $jsonEncodableStringifier = new JsonEncodableStringifier(),
         );
         $stringifier->prependStringifier(

src/Stringifiers/DeclaredStringifier.php

@@ -0,0 +1,42 @@
+<?php
+
+/*
+ * This file is part of Respect/Stringifier.
+ * Copyright (c) Henrique Moody <henriquemoody@gmail.com>
+ * SPDX-License-Identifier: MIT
+ */
+
+declare(strict_types=1);
+
+namespace Respect\Stringifier\Stringifiers;
+
+use Respect\Stringifier\Quoter;
+use Respect\Stringifier\Stringifier;
+
+use function class_exists;
+use function enum_exists;
+use function interface_exists;
+use function is_string;
+use function trait_exists;
+
+final class DeclaredStringifier implements Stringifier
+{
+    public function __construct(
+        private readonly Quoter $quoter
+    ) {
+    }
+
+    public function stringify(mixed $raw, int $depth): ?string
+    {
+        if (!is_string($raw) || $this->isNotDeclared($raw)) {
+            return null;
+        }
+
+        return $this->quoter->quote($raw, $depth);
+    }
+
+    public function isNotDeclared(string $raw): bool
+    {
+        return !class_exists($raw) && !interface_exists($raw) && !trait_exists($raw) && !enum_exists($raw);
+    }
+}

tests/integration/stringify-declared.phpt

@@ -0,0 +1,19 @@
+--FILE--
+<?php
+
+declare(strict_types=1);
+
+require 'vendor/autoload.php';
+
+outputMultiple(
+    Traversable::class,
+    ArrayIterator::class,
+    BasicEnumeration::class,
+    Respect\Stringifier\Helpers\ObjectHelper::class,
+);
+?>
+--EXPECT--
+`Traversable`
+`ArrayIterator`
+`BasicEnumeration`
+`Respect\Stringifier\Helpers\ObjectHelper`

tests/unit/Stringifiers/DeclaredStringifierTest.php

@@ -0,0 +1,63 @@
+<?php
+
+/*
+ * This file is part of Respect/Stringifier.
+ * Copyright (c) Henrique Moody <henriquemoody@gmail.com>
+ * SPDX-License-Identifier: MIT
+ */
+
+declare(strict_types=1);
+
+namespace Respect\Stringifier\Test\Unit\Stringifiers;
+
+use ArrayObject;
+use BasicEnumeration;
+use Countable;
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+use Respect\Stringifier\Helpers\ObjectHelper;
+use Respect\Stringifier\Stringifiers\DeclaredStringifier;
+use Respect\Stringifier\Test\Double\FakeQuoter;
+
+#[CoversClass(DeclaredStringifier::class)]
+final class DeclaredStringifierTest extends TestCase
+{
+    private const DEPTH = 0;
+
+    #[Test]
+    public function itShouldNotStringifyWhenRawValueIsNotExists(): void
+    {
+        $sut = new DeclaredStringifier(new FakeQuoter());
+
+        self::assertNull($sut->stringify('NotAClassInterfaceTraitOrEnum', self::DEPTH));
+    }
+
+    #[Test]
+    #[DataProvider('existsRawValuesProvider')]
+    public function itShouldStringifyWhenRawValueIsExists(string $raw): void
+    {
+        $quoter = new FakeQuoter();
+
+        $sut = new DeclaredStringifier($quoter);
+
+        $actual = $sut->stringify($raw, self::DEPTH);
+        $expected = $quoter->quote($raw, self::DEPTH);
+
+        self::assertEquals($expected, $actual);
+    }
+
+    /**
+     * @return array<int, array<int, string>>
+     */
+    public static function existsRawValuesProvider(): array
+    {
+        return [
+            [ArrayObject::class],
+            [Countable::class],
+            [BasicEnumeration::class],
+            [ObjectHelper::class],
+        ];
+    }
+}