Added CodeTransformerKernel

Author: WalterWoshid

src/CodeTransformerKernel.php

@@ -0,0 +1,45 @@
+<?php
+
+namespace Okapi\CodeTransformer;
+
+use Okapi\Singleton\Singleton;
+
+/**
+ * # Code Transformer Kernel
+ *
+ * The `CodeTransformerKernel` is the heart of the Code Transformer library.
+ * It manages an environment for Code Transformation.
+ *
+ * 1. Extends this class and define a list of transformers in the
+ *    `$transformers` property.
+ * 2. Call the `init()` method early in the application lifecycle.
+ */
+abstract class CodeTransformerKernel
+{
+    use Singleton;
+
+    /**
+     * List of transformers to be applied.
+     *
+     * @var class-string<Transformer>[]
+     */
+    protected array $transformers = [];
+
+    /**
+     * Initialize the kernel.
+     *
+     * @param string|null $cacheDir      The cache directory.
+     *                                   <br><b>Default:</b> ROOT_DIR/cache/code-transformer<br>
+     * @param int|null    $cacheFileMode The cache file mode.
+     *                                   <br><b>Default:</b> 0777 & ~{@link umask()}<br>
+     * @param bool|null   $debug         Enable debug mode. This will disable the cache.
+     *                                   <br><b>Default:</b> false<br>
+     *
+     * @return void
+     */
+    public static function init(
+        ?string $cacheDir,
+        ?int    $cacheFileMode = null,
+        bool    $debug = false,
+    ): void {}
+}