[8.5] Add locale_is_right_to_left

src/Php85/Php85.php

@@ -13,6 +13,7 @@
 
 /**
  * @author Pierre Ambroise <[email protected]>
+ * @author Alexander Schranz <[email protected]>
  *
  * @internal
  */
@@ -47,4 +48,54 @@ public static function array_last(array $array)
     {
         return $array ? current(array_slice($array, -1)) : null;
     }
+
+    public static function locale_is_right_to_left(string $locale): bool {
+        static $rtlScripts = [
+            'Adlm', 'Arab', 'Armi', 'Hebr', 'Mani', 'Mend', 'Nkoo',
+            'Phnx', 'Rohg', 'Samr', 'Syrc', 'Thaa',
+        ];
+
+        static $languageToLikelyRtlScript = [
+            'ar' => 'Arab', // Arabic
+            'fa' => 'Arab', // Persian (Farsi)
+            'ur' => 'Arab', // Urdu
+            'ps' => 'Arab', // Pashto
+            'sd' => 'Arab', // Sindhi
+            'ug' => 'Arab', // Uyghur
+            'ckb' => 'Arab', // Sorani Kurdish
+            'he' => 'Hebr', // Hebrew
+            'yi' => 'Hebr', // Yiddish
+            'dv' => 'Thaa', // Dhivehi
+            'nqo' => 'Nkoo', // N'Ko
+        ];
+
+        if (empty($locale)) {
+            return false;
+        }
+
+        $localeParts = preg_split('/[_-]/', $locale);
+        $language = strtolower($localeParts[0] ?? '');
+        $script = null;
+
+        foreach ($localeParts as $part) {
+            if (strlen($part) === 4 && ctype_alpha($part)) {
+                $script = ucfirst(strtolower($part));
+                break;
+            }
+        }
+
+        if ($script === null) {
+            $script = $languageToLikelyScript[$language] ?? null;
+        }
+
+        if ($script === null) {
+            if (in_array($language, ['ar', 'he', 'fa', 'ur', 'ps', 'sd', 'ug', 'ckb', 'yi', 'dv'])) {
+                 return true;
+            }
+
+            return false;
+        }
+
+        return in_array($script, $rtlScripts, true);
+    }
 }

src/Php85/bootstrap.php

@@ -30,3 +30,7 @@ function array_first(array $array) { return p\Php85::array_first($array); }
 if (!function_exists('array_last')) {
     function array_last(array $array) { return p\Php85::array_last($array); }
 }
+
+if (!function_exists('locale_is_right_to_left')) {
+    function locale_is_right_to_left(string $locale): bool { return p\Php85::locale_is_right_to_left($locale); }
+}

tests/Php85/Php85Test.php

@@ -116,6 +116,25 @@ public function testArrayFirstArrayLast()
         $this->assertTrue(array_first([true, new \stdClass]));
         $this->assertEquals(new \stdClass(), array_last([true, new \stdClass]));
     }
+
+    public function testLocaleIsRightToLeft(): void
+    {
+        $this->assertTrue(locale_is_right_to_left('ar'));
+        $this->assertTrue(locale_is_right_to_left('he'));
+        $this->assertTrue(locale_is_right_to_left('fa'));
+        $this->assertTrue(locale_is_right_to_left('ur'));
+        $this->assertTrue(locale_is_right_to_left('ps'));
+        $this->assertTrue(locale_is_right_to_left('sd'));
+        $this->assertTrue(locale_is_right_to_left('ug'));
+        $this->assertTrue(locale_is_right_to_left('ckb'));
+        $this->assertTrue(locale_is_right_to_left('yi'));
+        $this->assertTrue(locale_is_right_to_left('dv'));
+        $this->assertTrue(locale_is_right_to_left('ku_arab'));
+        $this->assertTrue(locale_is_right_to_left('ku-arab'));
+
+        $this->assertFalse(locale_is_right_to_left('en'));
+        $this->assertFalse(locale_is_right_to_left('fr'));
+    }
 }
 
 class TestHandler