[String] Check if function exists before declaring it

Author: Nyholm

Resources/functions.php

@@ -11,22 +11,28 @@
 
 namespace Symfony\Component\String;
 
-function u(?string $string = ''): UnicodeString
-{
-    return new UnicodeString($string ?? '');
+if (!\function_exists(u::class)) {
+    function u(?string $string = ''): UnicodeString
+    {
+        return new UnicodeString($string ?? '');
+    }
 }
 
-function b(?string $string = ''): ByteString
-{
-    return new ByteString($string ?? '');
+if (!\function_exists(b::class)) {
+    function b(?string $string = ''): ByteString
+    {
+        return new ByteString($string ?? '');
+    }
 }
 
-/**
- * @return UnicodeString|ByteString
- */
-function s(?string $string = ''): AbstractString
-{
-    $string = $string ?? '';
+if (!\function_exists(s::class)) {
+    /**
+     * @return UnicodeString|ByteString
+     */
+    function s(?string $string = ''): AbstractString
+    {
+        $string = $string ?? '';
 
-    return preg_match('//u', $string) ? new UnicodeString($string) : new ByteString($string);
+        return preg_match('//u', $string) ? new UnicodeString($string) : new ByteString($string);
+    }
 }