diff --git a/composer.json b/composer.json
index 9160a98..11822e3 100644
--- a/composer.json
+++ b/composer.json
@@ -12,10 +12,10 @@
     }
   ],
   "require": {
-    "php": ">8.0",
+    "php": ">8.0.1",
     "ext-mbstring": "*",
-    "toolkit/fsutil":"~1.0",
-    "toolkit/stdlib":"~1.0"
+    "toolkit/fsutil":"~2.0",
+    "toolkit/stdlib":"~2.0"
   },
   "autoload": {
     "psr-4": {
diff --git a/src/AbstractTemplate.php b/src/AbstractTemplate.php
index add4c63..de15c8d 100644
--- a/src/AbstractTemplate.php
+++ b/src/AbstractTemplate.php
@@ -62,7 +62,7 @@ abstract class AbstractTemplate implements TemplateInterface
      *
      * @return static
      */
-    public static function new(array $config = []): self
+    public static function new(array $config = []): static
     {
         return new static($config);
     }
@@ -82,7 +82,7 @@ public function __construct(array $config = [])
      *
      * @return $this
      */
-    public function configThis(callable $fn): self
+    public function configThis(callable $fn): static
     {
         $fn($this);
         return $this;
@@ -242,7 +242,7 @@ public function setGlobalVars(array $globalVars): void
      *
      * @return AbstractTemplate
      */
-    public function setPathResolver(callable $pathResolver): self
+    public function setPathResolver(callable $pathResolver): static
     {
         $this->pathResolver = $pathResolver;
         return $this;
diff --git a/src/Compiler/AbstractCompiler.php b/src/Compiler/AbstractCompiler.php
index 337da23..4228bad 100644
--- a/src/Compiler/AbstractCompiler.php
+++ b/src/Compiler/AbstractCompiler.php
@@ -62,19 +62,36 @@ abstract class AbstractCompiler implements CompilerInterface
     /**
      * custom directive, control statement token.
      *
-     * eg: implement include()
+     * -----
+     * eg: implements: `include('parts/header.tpl')`
+     *
+     * ```php
+     * $compiler->addDirective('include', function(string $body, string $name): string {
+     *      // $name : 'include'
+     *      // $body : "('parts/header.tpl')"
+     *      // do something...
+     * });
+     * ```
      *
      * @var array{string, callable(string, string): string}
      */
     public array $customDirectives = [];
 
+    /**
+     * @return static
+     */
+    public static function new(): static
+    {
+        return new static();
+    }
+
     /**
      * @param string $open
      * @param string $close
      *
      * @return $this
      */
-    public function setOpenCloseTag(string $open, string $close): self
+    public function setOpenCloseTag(string $open, string $close): static
     {
         $this->openTag  = $open;
         $this->closeTag = $close;
@@ -173,18 +190,18 @@ public function addFilter(string $name, string $callExpr): self
      * @param string $name
      * @param callable $handler
      *
-     * @return $this
+     * @return static
      */
-    public function addDirective(string $name, callable $handler): self
+    public function addDirective(string $name, callable $handler): static
     {
         $this->customDirectives[$name] = $handler;
         return $this;
     }
 
     /**
-     * @return $this
+     * @return static
      */
-    public function disableEchoFilter(): self
+    public function disableEchoFilter(): static
     {
         $this->echoFilterFunc = self::RAW_OUTPUT;
         return $this;
diff --git a/src/Compiler/LineCompiler.php b/src/Compiler/LineCompiler.php
index a21897f..4597da9 100644
--- a/src/Compiler/LineCompiler.php
+++ b/src/Compiler/LineCompiler.php
@@ -29,14 +29,6 @@ class LineCompiler extends AbstractCompiler
      */
     private bool $insideTag = false;
 
-    /**
-     * @return static
-     */
-    public static function new(): self
-    {
-        return new self();
-    }
-
     /**
      * compile template contents to raw PHP template codes
      *
diff --git a/src/Compiler/PregCompiler.php b/src/Compiler/PregCompiler.php
index 04deef0..2e45326 100644
--- a/src/Compiler/PregCompiler.php
+++ b/src/Compiler/PregCompiler.php
@@ -26,21 +26,13 @@ class PregCompiler extends AbstractCompiler
     private string $openTagE = '\{\{';
     private string $closeTagE = '\}\}';
 
-    /**
-     * @return static
-     */
-    public static function new(): self
-    {
-        return new self();
-    }
-
     /**
      * @param string $open
      * @param string $close
      *
      * @return $this
      */
-    public function setOpenCloseTag(string $open, string $close): self
+    public function setOpenCloseTag(string $open, string $close): static
     {
         parent::setOpenCloseTag($open, $close);
 
@@ -113,11 +105,6 @@ public function parseCodeBlock(string $block): string
             return self::PHP_TAG_OPEN . ' } ' . self::PHP_TAG_CLOSE;
         }
 
-        // comments block. `{{# comments #}}`
-        // if ($block[0] === '#' && str_ends_with($block, '#')) {
-        //     return '';
-        // }
-
         $isInline = !str_contains($trimmed, "\n");
         $kwPattern = Token::getBlockNamePattern();
 
diff --git a/src/Contract/CompilerInterface.php b/src/Contract/CompilerInterface.php
index b8a2672..0b958dd 100644
--- a/src/Contract/CompilerInterface.php
+++ b/src/Contract/CompilerInterface.php
@@ -15,12 +15,20 @@ interface CompilerInterface
      *
      * @return $this
      */
-    public function setOpenCloseTag(string $open, string $close): self;
+    public function setOpenCloseTag(string $open, string $close): static;
 
     /**
      * @return $this
      */
-    public function disableEchoFilter(): self;
+    public function disableEchoFilter(): static;
+
+    /**
+     * @param string $name
+     * @param callable $handler
+     *
+     * @return static
+     */
+    public function addDirective(string $name, callable $handler): static;
 
     /**
      * compile template contents to raw PHP template codes
diff --git a/src/EasyTemplate.php b/src/EasyTemplate.php
index 1e64272..5504319 100644
--- a/src/EasyTemplate.php
+++ b/src/EasyTemplate.php
@@ -79,9 +79,10 @@ protected function init(CompilerInterface $compiler): void
     {
         // add built-in filters
         $this->addFilters([
-            'upper' => 'strtoupper',
-            'lower' => 'strtolower',
-            'nl'    => function ($str): string {
+            'upper'  => 'strtoupper',
+            'lower'  => 'strtolower',
+            'escape' => 'htmlspecialchars',
+            'nl'     => function ($str): string {
                 return $str . "\n";
             },
         ]);
diff --git a/src/Extended/ExtendLoader.php b/src/Extended/ExtendLoader.php
new file mode 100644
index 0000000..d605022
--- /dev/null
+++ b/src/Extended/ExtendLoader.php
@@ -0,0 +1,10 @@
+<?php declare(strict_types=1);
+
+namespace PhpPkg\EasyTpl\Extended;
+
+use Toolkit\Stdlib\Obj\Traits\AutoConfigTrait;
+
+class ExtendLoader
+{
+    use AutoConfigTrait;
+}
diff --git a/src/Extended/ExtendedTemplate.php b/src/Extended/ExtendedTemplate.php
new file mode 100644
index 0000000..c83091c
--- /dev/null
+++ b/src/Extended/ExtendedTemplate.php
@@ -0,0 +1,51 @@
+<?php declare(strict_types=1);
+
+namespace PhpPkg\EasyTpl\Extended;
+
+use PhpPkg\EasyTpl\Contract\CompilerInterface;
+use PhpPkg\EasyTpl\EasyTemplate;
+use function sprintf;
+use function trim;
+
+/**
+ * Class ExtendedTemplate TODO
+ *
+ * @package PhpPkg\EasyTpl
+ */
+class ExtendedTemplate extends EasyTemplate
+{
+    public const BLOCK_VAR_PREFIX = 'TPL_BLOCK_';
+
+    private $currentBlock = '';
+
+    protected function init(CompilerInterface $compiler): void
+    {
+        parent::init($compiler);
+
+        $compiler
+            ->addDirective('extend', function (string $tplName) {
+                return ExtendLoader::new()->handle($tplName);
+            })
+            ->addDirective('extends', function () {
+
+            })
+            ->addDirective('block', function (string $body) {
+                $this->currentBlock = trim($body, '() ');
+
+                return sprintf('$this->startBlock(%s);', $this->currentBlock);
+            })
+            ->addDirective('endblock', function () {
+                return '$this->endBlock();';
+            });
+    }
+
+    protected function startBlock(string $name): void
+    {
+
+    }
+
+    protected function endBlock(): void
+    {
+
+    }
+}
\ No newline at end of file
diff --git a/src/Extended/LayoutTemplate.php b/src/Extended/LayoutTemplate.php
new file mode 100644
index 0000000..e0acc55
--- /dev/null
+++ b/src/Extended/LayoutTemplate.php
@@ -0,0 +1,27 @@
+<?php declare(strict_types=1);
+
+namespace PhpPkg\EasyTpl\Extended;
+
+use PhpPkg\EasyTpl\Contract\CompilerInterface;
+use PhpPkg\EasyTpl\EasyTemplate;
+
+/**
+ * Class LayoutTemplate TODO
+ * @package PhpPkg\EasyTpl\Extended
+ */
+class LayoutTemplate extends EasyTemplate
+{
+
+    protected function init(CompilerInterface $compiler): void
+    {
+        parent::init($compiler);
+
+        $compiler
+            ->addDirective('layout', function (string $tplName) {
+                return ExtendLoader::new()->handle();
+            })
+            ->addDirective('contents', function () {
+                return '$this->contents();';
+            });
+    }
+}
diff --git a/test/Compiler/PregCompilerTest.php b/test/Compiler/PregCompilerTest.php
index 648921a..c38aaae 100644
--- a/test/Compiler/PregCompilerTest.php
+++ b/test/Compiler/PregCompilerTest.php
@@ -177,67 +177,6 @@ public function testCompile_comments():void
         }
     }
 
-    public function testCompile_customDirective():void
-    {
-        $p = new PregCompiler();
-        $p->addDirective('include', function (string $body, string $name) {
-            return '$this->' . $name . $body;
-        });
-
-        $tests = [
-            ['{{ include("header.tpl") }}', '<?php $this->include("header.tpl") ?>'],
-            ['{{ include("header.tpl", [
-   "key1" => "value1",
-]) }}', '<?php
-$this->include("header.tpl", [
-   "key1" => "value1",
-])
-?>'],
-        ];
-        foreach ($tests as [$in, $out]) {
-            $this->assertEquals($out, $p->compile($in));
-        }
-    }
-
-    public function testCompile_has_comments():void
-    {
-        $p = new PregCompiler();
-
-        $str = <<<'TXT'
-{{# comments #}} hello
-TXT;
-        $out = $p->compile($str);
-        $this->assertStringNotContainsString('{{#', $out);
-        $this->assertStringNotContainsString('comments', $out);
-        $this->assertEquals(' hello', $out);
-
-        $str = <<<'TXT'
-{{# multi
- line
-  comments
-#}} hello
-TXT;
-        $out = $p->compile($str);
-        $this->assertStringNotContainsString('{{#', $out);
-        $this->assertStringNotContainsString('comments', $out);
-        $this->assertEquals(' hello', $out);
-
-        $str = <<<'TXT'
-{{ foreach ($vars as $var): }}
-{{#
-comments
- newInfo.incr{{ $var | ucfirst }}({{ $var }});
-#}}
-public void {{ $var | ucfirst }}(Integer value) {
-    {{ $var }} += value;
-}
-{{ endforeach }}
-TXT;
-        $out = $p->compile($str);
-        $this->assertStringNotContainsString('{{#', $out);
-        $this->assertStringNotContainsString('comments', $out);
-    }
-
     public function testCompile_if_block():void
     {
         $p = new PregCompiler();
@@ -339,4 +278,65 @@ public function testCompile_ml_define():void
             ,$compiled);
     }
 
+    public function testCompile_customDirective_include():void
+    {
+        $p = new PregCompiler();
+        $p->addDirective('include', function (string $body, string $name) {
+            return '$this->' . $name . $body;
+        });
+
+        $tests = [
+            ['{{ include("header.tpl") }}', '<?php $this->include("header.tpl") ?>'],
+            ['{{ include("header.tpl", [
+   "key1" => "value1",
+]) }}', '<?php
+$this->include("header.tpl", [
+   "key1" => "value1",
+])
+?>'],
+        ];
+        foreach ($tests as [$in, $out]) {
+            $this->assertEquals($out, $p->compile($in));
+        }
+    }
+
+    public function testCompile_has_comments():void
+    {
+        $p = new PregCompiler();
+
+        $str = <<<'TXT'
+{{# comments #}} hello
+TXT;
+        $out = $p->compile($str);
+        $this->assertStringNotContainsString('{{#', $out);
+        $this->assertStringNotContainsString('comments', $out);
+        $this->assertEquals(' hello', $out);
+
+        $str = <<<'TXT'
+{{# multi
+ line
+  comments
+#}} hello
+TXT;
+        $out = $p->compile($str);
+        $this->assertStringNotContainsString('{{#', $out);
+        $this->assertStringNotContainsString('comments', $out);
+        $this->assertEquals(' hello', $out);
+
+        $str = <<<'TXT'
+{{ foreach ($vars as $var): }}
+{{#
+comments
+ newInfo.incr{{ $var | ucfirst }}({{ $var }});
+#}}
+public void {{ $var | ucfirst }}(Integer value) {
+    {{ $var }} += value;
+}
+{{ endforeach }}
+TXT;
+        $out = $p->compile($str);
+        $this->assertStringNotContainsString('{{#', $out);
+        $this->assertStringNotContainsString('comments', $out);
+    }
+
 }
diff --git a/test/EasyTemplateTest.php b/test/EasyTemplateTest.php
index d3bcf18..ea1dc9a 100644
--- a/test/EasyTemplateTest.php
+++ b/test/EasyTemplateTest.php
@@ -240,7 +240,7 @@ public function testRender_foreach(): void
     public function testRender_include_file(): void
     {
         $t = new EasyTemplate([
-            'tplDir' => __DIR__ . '/testdata',
+            'tplDir' => __DIR__ . '/testdata/includes',
         ]);
 
         $result = $t->renderFile('home', ['name' => 'inhere']);
diff --git a/test/testdata/extends/home.php b/test/testdata/extends/home.php
new file mode 100644
index 0000000..56f652a
--- /dev/null
+++ b/test/testdata/extends/home.php
@@ -0,0 +1,12 @@
+
+<?php $this->extends('layouts/layout.php') ?>
+
+<?php $this->block('body') ?>
+on home: block body;
+<?php $this->endblock() ?>
+
+<?php $this->block('footer') ?>
+on home: block footer;
+<?php $this->endblock() ?>
+
+
diff --git a/test/testdata/extends/home.tpl b/test/testdata/extends/home.tpl
new file mode 100644
index 0000000..f6d161b
--- /dev/null
+++ b/test/testdata/extends/home.tpl
@@ -0,0 +1,10 @@
+
+{{ extends('layouts/layout.tpl') }}
+
+{{ block 'body' }}
+on home: block body;
+{{ endblock; }}
+
+{{ block 'footer' }}
+on home: block footer;
+{{ endblock; }}
diff --git a/test/testdata/extends/layouts/layout.php b/test/testdata/extends/layouts/layout.php
new file mode 100644
index 0000000..b286cbc
--- /dev/null
+++ b/test/testdata/extends/layouts/layout.php
@@ -0,0 +1,20 @@
+this is an layout file.
+
+--- head
+
+<?php $this->block('header') ?>
+on layout: block header;
+<?php $this->endblock(); ?>
+
+--- body
+
+<?php $this->block('body') ?>
+on layout: block body;
+<?php $this->endblock(); ?>
+
+--- footer
+
+<?php $this->block('footer') ?>
+on layout: block footer;
+<?php $this->endblock(); ?>
+
diff --git a/test/testdata/extends/layouts/layout.tpl b/test/testdata/extends/layouts/layout.tpl
new file mode 100644
index 0000000..68adbd7
--- /dev/null
+++ b/test/testdata/extends/layouts/layout.tpl
@@ -0,0 +1,14 @@
+{{ block 'header' }}
+    on layout: block header;
+{{ endblock }}
+
+this is an layout file.
+
+{{ block 'body' }}
+    on layout: block body;
+{{ endblock }}
+
+{{ block 'footer' }}
+    on layout: block footer;
+{{ endblock }}
+
diff --git a/test/testdata/home.tpl b/test/testdata/includes/home.tpl
similarity index 100%
rename from test/testdata/home.tpl
rename to test/testdata/includes/home.tpl
diff --git a/test/testdata/parts/header.tpl b/test/testdata/includes/parts/header.tpl
similarity index 100%
rename from test/testdata/parts/header.tpl
rename to test/testdata/includes/parts/header.tpl