Enhancement: Extract Pattern

src/JsonPointer.php

@@ -38,7 +38,7 @@ private function __construct(ReferenceToken ...$referenceTokens)
      */
     public static function fromJsonString(string $value): self
     {
-        if (1 !== \preg_match('/^(\/(?P<referenceToken>((?P<unescaped>[\x00-\x2E]|[\x30-\x7D]|[\x7F-\x{10FFFF}])|(?P<escaped>~[01]))*))*$/u', $value)) {
+        if (1 !== \preg_match(Pattern::JSON_POINTER_JSON_STRING, $value)) {
             throw Exception\InvalidJsonPointer::fromJsonString($value);
         }
 

src/Pattern.php

@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Copyright (c) 2020-2022 Andreas Möller
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE.md file that was distributed with this source code.
+ *
+ * @see https://github.com/ergebnis/json-pointer
+ */
+
+namespace Ergebnis\Json\Pointer;
+
+/**
+ * @internal
+ */
+final class Pattern
+{
+    /**
+     * @see https://datatracker.ietf.org/doc/html/rfc6901#section-3
+     */
+    public const JSON_POINTER_JSON_STRING = '/^(?P<jsonPointer>(\/(?P<referenceToken>((?P<unescaped>[\x00-\x2E]|[\x30-\x7D]|[\x7F-\x{10FFFF}])|(?P<escaped>~[01]))*))*)$/u';
+
+    /**
+     * @see https://datatracker.ietf.org/doc/html/rfc6901#section-3
+     */
+    public const REFERENCE_TOKEN = '/^(?P<referenceToken>((?P<unescaped>[\x00-\x2E]|[\x30-\x7D]|[\x7F-\x{10FFFF}])|(?P<escaped>~[01]))*)$/u';
+}

src/ReferenceToken.php

@@ -46,7 +46,7 @@ public static function fromInt(int $value): self
      */
     public static function fromJsonString(string $value): self
     {
-        if (1 !== \preg_match('/^(?P<referenceToken>((?P<unescaped>[\x00-\x2E]|[\x30-\x7D]|[\x7F-\x{10FFFF}])|(?P<escaped>~[01]))*)$/u', $value)) {
+        if (1 !== \preg_match(Pattern::REFERENCE_TOKEN, $value)) {
             throw Exception\InvalidReferenceToken::fromJsonString($value);
         }
 

test/Unit/PatternTest.php

@@ -0,0 +1,54 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Copyright (c) 2020-2022 Andreas Möller
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE.md file that was distributed with this source code.
+ *
+ * @see https://github.com/ergebnis/json-pointer
+ */
+
+namespace Ergebnis\Json\Pointer\Test\Unit;
+
+use Ergebnis\Json\Pointer\Pattern;
+use PHPUnit\Framework;
+
+/**
+ * @internal
+ *
+ * @covers \Ergebnis\Json\Pointer\Pattern
+ */
+final class PatternTest extends Framework\TestCase
+{
+    public function testJsonPointerJsonStringEqualsPattern(): void
+    {
+        $referenceToken = self::referenceToken();
+
+        $expected = "/^(?P<jsonPointer>(\\/{$referenceToken})*)$/u";
+
+        self::assertSame($expected, Pattern::JSON_POINTER_JSON_STRING);
+    }
+
+    public function testReferenceTokenEqualsPattern(): void
+    {
+        $referenceToken = self::referenceToken();
+
+        $expected = "/^{$referenceToken}$/u";
+
+        self::assertSame($expected, Pattern::REFERENCE_TOKEN);
+    }
+
+    /**
+     * @see https://datatracker.ietf.org/doc/html/rfc6901#section-3
+     */
+    private static function referenceToken(): string
+    {
+        $unescaped = '(?P<unescaped>[\x00-\x2E]|[\x30-\x7D]|[\x7F-\x{10FFFF}])';
+        $escaped = '(?P<escaped>~[01])';
+
+        return "(?P<referenceToken>({$unescaped}|{$escaped})*)";
+    }
+}