new example: how to use different types of callbacks when creating co…

…routines

Signed-off-by: Demin Yin <deminy@deminy.net>

README.md

@@ -41,7 +41,7 @@ docker compose exec -ti client bash # Get a Bash shell in the client container.
         * [This example](https://github.com/deminy/swoole-by-examples/blob/master/examples/io/blocking-vs-non-blocking.php) shows how the _return_ statement is treated differently in Swoole. As you can see in the example, a function call could return a value back first before finishing its execution.
     * coroutines
         * create coroutines
-            * use different callbacks to create coroutines
+            * [use different types of callbacks when creating coroutines](https://github.com/deminy/swoole-by-examples/blob/master/examples/csp/coroutines/creation-2.php)
             * [use different functions/methods to create coroutines](https://github.com/deminy/swoole-by-examples/blob/master/examples/csp/coroutines/creation-1.php)
         * enable coroutines
         * [coroutines in a for loop](https://github.com/deminy/swoole-by-examples/blob/master/examples/csp/coroutines/for.php)

examples/csp/coroutines/creation-2.php

@@ -0,0 +1,68 @@
+#!/usr/bin/env php
+<?php
+
+declare(strict_types=1);
+
+/**
+ * This example shows how to use different types of callbacks when creating coroutines.
+ *
+ * How to run this script:
+ *     docker compose exec -t client bash -c "./csp/coroutines/creation-2.php"
+ *
+ * @see https://www.php.net/manual/en/language.types.callable.php Callbacks / Callables
+ */
+
+use Swoole\Coroutine;
+
+use function Swoole\Coroutine\run;
+
+// Define a callback function.
+function callbackFunction(int $i): void
+{
+    echo $i;
+}
+
+// Define a class with both static and non-static callback methods included.
+class callbackClass
+{
+    public function callbackMethod(int $i): void
+    {
+        echo $i;
+    }
+
+    public static function staticCallbackMethod(int $i): void
+    {
+        echo $i;
+    }
+}
+
+// An invokable class.
+class InvokableClass
+{
+    public function __invoke(int $i): void
+    {
+        echo $i;
+    }
+}
+
+run(function () {
+    // Type 1: A simple callback function defined directly within the code block.
+    Coroutine::create(function () {echo 1; });
+
+    // Type 2: A simple callback function defined somewhere previously.
+    Coroutine::create('callbackFunction', 2);
+
+    // Type 3: Use object method call as callback.
+    Coroutine::create([new callbackClass(), 'callbackMethod'], 3);
+
+    // Type 4: Use static class method call as callback.
+    Coroutine::create(['callbackClass', 'staticCallbackMethod'], 4);
+
+    // Type 5: Use static class method call as callback.
+    Coroutine::create('callbackClass::staticCallbackMethod', 5);
+
+    // Type 6: Objects implementing __invoke can be used as callbacks.
+    Coroutine::create(new InvokableClass(), 6);
+});
+
+echo PHP_EOL;