diff --git a/composer.json b/composer.json
index bab2430..7deb027 100644
--- a/composer.json
+++ b/composer.json
@@ -4,7 +4,7 @@
     "description": "Cytro - fast template engine for PHP",
     "homepage": "http://bzick.github.io/cytro/",
     "keywords": ["cytro", "template", "templating"],
-    "license": "MIT",
+    "license": "BSD-3",
     "authors": [
         {
             "name": "Ivan Shalganov",
diff --git a/src/Cytro.php b/src/Cytro.php
index 7960c93..d2a2546 100644
--- a/src/Cytro.php
+++ b/src/Cytro.php
@@ -1,4 +1,12 @@
 <?php
+/*
+ * This file is part of Cytro.
+ *
+ * (c) 2013 Ivan Shalganov
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
 use Cytro\Template,
     Cytro\ProviderInterface;
 
diff --git a/src/Cytro/Compiler.php b/src/Cytro/Compiler.php
index 0946200..f0d1d04 100644
--- a/src/Cytro/Compiler.php
+++ b/src/Cytro/Compiler.php
@@ -1,4 +1,12 @@
 <?php
+/*
+ * This file is part of Cytro.
+ *
+ * (c) 2013 Ivan Shalganov
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
 namespace Cytro;
 use Cytro\Tokenizer;
 use Cytro\Template;
@@ -6,6 +14,7 @@ use Cytro\Scope;
 
 /**
  * Compilers collection
+ * @package Cytro
  */
 class Compiler {
     /**
@@ -18,7 +27,7 @@ class Compiler {
      * @return string
      */
     public static function tagInclude(Tokenizer $tokens, Template $tpl) {
-        $cname = $tpl->parseFirstArg($tokens, $name);
+        $cname = $tpl->parsePlainArg($tokens, $name);
         $p = $tpl->parseParams($tokens);
         if($p) { // if we have additionally variables
             if($name && ($tpl->getStorage()->getOptions() & \Cytro::FORCE_INCLUDE)) { // if FORCE_INCLUDE enabled and template name known
@@ -371,7 +380,7 @@ class Compiler {
         if(!empty($tpl->_extends)) {
             throw new ImproperUseException("Only one {extends} allowed");
         }
-        $tpl_name = $tpl->parseFirstArg($tokens, $name);
+        $tpl_name = $tpl->parsePlainArg($tokens, $name);
         if(empty($tpl->_extended)) {
             $tpl->addPostCompile(__CLASS__."::extendBody");
         }
@@ -423,13 +432,14 @@ class Compiler {
     }
 
     /**
+     * Tag {use ...}
      * @param Tokenizer $tokens
      * @param Template $tpl
      * @throws ImproperUseException
      * @return string
      */
     public static function tagUse(Tokenizer $tokens, Template $tpl) {
-        $tpl->parseFirstArg($tokens, $name);
+        $tpl->parsePlainArg($tokens, $name);
         if($name) {
             $donor = $tpl->getStorage()->getRawTemplate()->load($name, false);
             $donor->_extended = true;
@@ -457,7 +467,7 @@ class Compiler {
      * @throws ImproperUseException
      */
     public static function tagBlockOpen(Tokenizer $tokens, Scope $scope) {
-        $p = $scope->tpl->parseFirstArg($tokens, $name);
+        $p = $scope->tpl->parsePlainArg($tokens, $name);
         $scope["name"]  = $name;
         $scope["cname"] = $p;
     }
@@ -750,7 +760,7 @@ class Compiler {
             $tokens->next();
         }
 
-        $tpl->parseFirstArg($tokens, $name);
+        $tpl->parsePlainArg($tokens, $name);
         if(!$name) {
             throw new ImproperUseException("Invalid usage tag {import}");
         }
diff --git a/src/Cytro/FSProvider.php b/src/Cytro/FSProvider.php
index 27292fb..213e9e8 100644
--- a/src/Cytro/FSProvider.php
+++ b/src/Cytro/FSProvider.php
@@ -1,4 +1,12 @@
 <?php
+/*
+ * This file is part of Cytro.
+ *
+ * (c) 2013 Ivan Shalganov
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
 namespace Cytro;
 
 use Cytro\ProviderInterface;
@@ -46,6 +54,10 @@ class FSProvider implements ProviderInterface {
         }
     }
 
+    /**
+     * @param string $template_dir directory of templates
+     * @throws \LogicException if directory doesn't exists
+     */
     public function __construct($template_dir) {
         if($_dir = realpath($template_dir)) {
             $this->_path = $_dir;
@@ -107,9 +119,9 @@ class FSProvider implements ProviderInterface {
     }
 
     /**
-     * Verify templates by change time
+     * Verify templates (check change time)
      *
-     * @param array $templates [template_name => modified, ...] By conversation you may trust the template's name
+     * @param array $templates [template_name => modified, ...] By conversation, you may trust the template's name
      * @return bool
      */
     public function verify(array $templates) {
diff --git a/src/Cytro/Modifier.php b/src/Cytro/Modifier.php
index dfdc9c4..7921446 100644
--- a/src/Cytro/Modifier.php
+++ b/src/Cytro/Modifier.php
@@ -12,8 +12,6 @@ namespace Cytro;
 /**
  * Collection of modifiers
  *
- * @package    aspect
- * @author     Ivan Shalganov <owner@bzick.net>
  */
 class Modifier {
 
@@ -84,9 +82,9 @@ class Modifier {
     /**
      * Crop string by length
      * UTF8 support
-     * @param string $string
-     * @param int $length
-     * @param string $etc
+     * @param string $string text witch will be truncate
+     * @param int $length maximum symbols of result string
+     * @param string $etc place holder truncated symbols
      * @param bool $by_words
      * @param bool $middle
      * @return string
@@ -116,7 +114,7 @@ class Modifier {
 
     /**
      * Strip spaces symbols on edge of string end multiple spaces in string
-     * @static
+     *
      * @param string $str
      * @param bool $to_line strip line ends
      * @return string
diff --git a/src/Cytro/ProviderInterface.php b/src/Cytro/ProviderInterface.php
index 4a67462..08b3747 100644
--- a/src/Cytro/ProviderInterface.php
+++ b/src/Cytro/ProviderInterface.php
@@ -1,4 +1,12 @@
 <?php
+/*
+ * This file is part of Cytro.
+ *
+ * (c) 2013 Ivan Shalganov
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
 namespace Cytro;
 
 interface ProviderInterface {
diff --git a/src/Cytro/Render.php b/src/Cytro/Render.php
index e160eb0..9910884 100644
--- a/src/Cytro/Render.php
+++ b/src/Cytro/Render.php
@@ -1,4 +1,12 @@
 <?php
+/*
+ * This file is part of Cytro.
+ *
+ * (c) 2013 Ivan Shalganov
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
 namespace Cytro;
 use Cytro;
 
@@ -22,20 +30,34 @@ class Render extends \ArrayObject {
      * @var string
      */
     protected $_name = 'runtime';
+    /**
+     * Provider's schema
+     * @var bool
+     */
     protected $_scm = false;
+    /**
+     * Basic template name
+     * @var string
+     */
     protected $_base_name = 'runtime';
     /**
      * @var Cytro
      */
-    protected $_aspect;
+    protected $_cytro;
     /**
      * Timestamp of compilation
      * @var float
      */
     protected $_time = 0.0;
 
+    /**
+     * @var array depends list
+     */
     protected $_depends = array();
 
+    /**
+     * @var int tempalte options (see Cytro options)
+     */
     protected $_options = 0;
 
     /**
@@ -45,15 +67,15 @@ class Render extends \ArrayObject {
     protected $_provider;
 
     /**
-     * @param Cytro $aspect
+     * @param Cytro $cytro
      * @param callable $code template body
      * @param array $props
      */
-    public function __construct(Cytro $aspect, \Closure $code, $props = array()) {
-        $this->_aspect = $aspect;
+    public function __construct(Cytro $cytro, \Closure $code, $props = array()) {
+        $this->_cytro = $cytro;
         $props += self::$_props;
         $this->_name = $props["name"];
-        $this->_provider = $this->_aspect->getProvider($props["scm"]);
+        $this->_provider = $this->_cytro->getProvider($props["scm"]);
         $this->_scm = $props["scm"];
         $this->_time = $props["time"];
         $this->_depends = $props["depends"];
@@ -65,7 +87,7 @@ class Render extends \ArrayObject {
      * @return Cytro
      */
     public function getStorage() {
-        return $this->_aspect;
+        return $this->_cytro;
     }
 
     public function getDepends() {
@@ -113,12 +135,12 @@ class Render extends \ArrayObject {
      * @return bool
      */
     public function isValid() {
-        $provider = $this->_aspect->getProvider(strstr($this->_name, ":"), true);
+        $provider = $this->_cytro->getProvider(strstr($this->_name, ":"), true);
         if($provider->getLastModified($this->_name) >= $this->_time) {
             return false;
         }
         foreach($this->_depends as $tpl => $time) {
-            if($this->_aspect->getTemplate($tpl)->getTime() !== $time) {
+            if($this->_cytro->getTemplate($tpl)->getTime() !== $time) {
                 return false;
             }
         }
diff --git a/src/Cytro/Scope.php b/src/Cytro/Scope.php
index b7e65fa..6bd1905 100644
--- a/src/Cytro/Scope.php
+++ b/src/Cytro/Scope.php
@@ -1,4 +1,12 @@
 <?php
+/*
+ * This file is part of Cytro.
+ *
+ * (c) 2013 Ivan Shalganov
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
 namespace Cytro;
 
 /**
diff --git a/src/Cytro/Template.php b/src/Cytro/Template.php
index 49f652f..c0f7ee0 100644
--- a/src/Cytro/Template.php
+++ b/src/Cytro/Template.php
@@ -68,6 +68,7 @@ class Template extends Render {
      * Just factory
      *
      * @param \Cytro $aspect
+     * @param $options
      * @return Template
      */
     public static function factory(Cytro $aspect, $options) {
@@ -75,11 +76,12 @@ class Template extends Render {
     }
 
     /**
-     * @param Cytro $aspect Template storage
+     * @param Cytro $cytro Template storage
+     * @param $options
      */
-    public function __construct(Cytro $aspect, $options) {
-        $this->_aspect = $aspect;
-        $this->_options = $this->_aspect->getOptions();
+    public function __construct(Cytro $cytro, $options) {
+        $this->_cytro = $cytro;
+        $this->_options = $this->_cytro->getOptions();
     }
 
     /**
@@ -96,7 +98,7 @@ class Template extends Render {
         } else {
             $this->_base_name = $name;
         }
-        $this->_provider = $this->_aspect->getProvider($provider);
+        $this->_provider = $this->_cytro->getProvider($provider);
         $this->_src = $this->_provider->getSource($name, $this->_time);
         if($compile) {
             $this->compile();
@@ -143,12 +145,12 @@ class Template extends Render {
                     $pos = $end + 1; // trying finding tags after the comment block
                     continue 2;
             }
-            $end = strpos($this->_src, '}', $start); // search close-char of the tag
+            $end = strpos($this->_src, '}', $start); // search close-symbol of the tag
             if(!$end) { // if unexpected end of template
                 throw new CompileException("Unclosed tag in line {$this->_line}", 0, 1, $this->_name, $this->_line);
             }
-            $frag .= substr($this->_src, $this->_pos, $start - $this->_pos);  // variable $frag contains chars after last '}' and next '{'
-            $tag = substr($this->_src, $start, $end - $start + 1); // variable $tag contains aspect tag '{...}'
+            $frag .= substr($this->_src, $this->_pos, $start - $this->_pos);  // variable $frag contains chars after previous '}' and current '{'
+            $tag = substr($this->_src, $start, $end - $start + 1); // variable $tag contains cytro tag '{...}'
             $this->_line += substr_count($this->_src, "\n", $this->_pos, $end - $start + 1); // count lines in $frag and $tag (using original text $code)
             $pos = $this->_pos = $end + 1; // move search-pointer to end of the tag
 
@@ -215,6 +217,11 @@ class Template extends Render {
         $this->_body .= str_replace("<?", '<?php echo "<?"; ?>'.PHP_EOL, $text);
     }
 
+    /**
+     * Append PHP_EOL after each '?>'
+     * @param int $code
+     * @return string
+     */
     private function _escapeCode($code) {
         $c = "";
         foreach(token_get_all($code) as $token) {
@@ -414,7 +421,7 @@ class Template extends Render {
             return $this->parseMacro($tokens, $name);
         }
 
-        if($act = $this->_aspect->getFunction($action)) { // call some function
+        if($act = $this->_cytro->getFunction($action)) { // call some function
             switch($act["type"]) {
                 case Cytro::BLOCK_COMPILER:
                     $scope = new Scope($action, $this, $this->_line, $act, count($this->_stack), $this->_body);
@@ -442,7 +449,7 @@ class Template extends Render {
                 return $this->_stack[$i]->tag($action, $tokens);
             }
         }
-        if($tags = $this->_aspect->getTagOwners($action)) { // unknown template tag
+        if($tags = $this->_cytro->getTagOwners($action)) { // unknown template tag
             throw new TokenizeException("Unexpected tag '$action' (this tag can be used with '".implode("', '", $tags)."')");
         } else {
             throw new TokenizeException("Unexpected tag $action");
@@ -496,7 +503,7 @@ class Template extends Render {
                 if($tokens->isSpecialVal()) {
                     $_exp .= $tokens->getAndNext();
                 } elseif($tokens->isNext("(")) {
-                    $func = $this->_aspect->getModifier($tokens->current());
+                    $func = $this->_cytro->getModifier($tokens->current());
                     $tokens->next();
                     $_exp .= $func.$this->parseArgs($tokens);
                 } else {
@@ -828,7 +835,7 @@ class Template extends Render {
      */
     public function parseModifier(Tokenizer $tokens, $value) {
         while($tokens->is("|")) {
-            $mods = $this->_aspect->getModifier( $tokens->getNext(Tokenizer::MACRO_STRING) );
+            $mods = $this->_cytro->getModifier( $tokens->getNext(Tokenizer::MACRO_STRING) );
             $tokens->next();
             $args = array();
 
@@ -1008,7 +1015,7 @@ class Template extends Render {
      * @param string $static
      * @return mixed|string
      */
-    public function parseFirstArg(Tokenizer $tokens, &$static) {
+    public function parsePlainArg(Tokenizer $tokens, &$static) {
         if($tokens->is(T_CONSTANT_ENCAPSED_STRING)) {
             if($tokens->isNext('|')) {
                 return $this->parseExp($tokens, true);
diff --git a/src/Cytro/Tokenizer.php b/src/Cytro/Tokenizer.php
index f42d7c6..2a3fd90 100644
--- a/src/Cytro/Tokenizer.php
+++ b/src/Cytro/Tokenizer.php
@@ -9,9 +9,16 @@
  */
 namespace Cytro;
 
+/**
+ * for <PHP 5.4 compatible
+ */
 defined('T_INSTEADOF')  || define('T_INSTEADOF', 341);
 defined('T_TRAIT')      || define('T_TRAIT', 355);
 defined('T_TRAIT_C')    || define('T_TRAIT_C', 365);
+/**
+ *  for PHP <5.5
+ */
+defined('T_YIELD')      || define('T_YIELD', 370);
 
 /**
  * Each token have structure
diff --git a/tests/cases/Cytro/ExtendsTemplateTest.php b/tests/cases/Cytro/ExtendsTemplateTest.php
index e6b84df..0c07ef1 100644
--- a/tests/cases/Cytro/ExtendsTemplateTest.php
+++ b/tests/cases/Cytro/ExtendsTemplateTest.php
@@ -11,11 +11,11 @@ class ExtendsTemplateTest extends TestCase {
                 "name"  => "level.0.tpl",
                 "level" => 0,
                 "blocks" => array(
-                    "b1" => "",
+                    "b1" => "default 5",
                     "b2" => "empty 0"
                 ),
                 "result" => array(
-                    "b1" => "",
+                    "b1" => "default 5",
                     "b2" => "empty 0"
                 ),
             ),
@@ -79,10 +79,27 @@ class ExtendsTemplateTest extends TestCase {
      * @group static-extend
      */
     public function testTemplateExtends() {
-        foreach(self::generate('{block "%s"}%s{/block}', '{extends "level.%d.tpl"}') as $name => $tpl) {
+        $vars = array(
+            "b1" => "b1",
+            "b2" => "b2",
+            "b3" => "b3",
+            "b4" => "b4",
+            "level" => "level",
+            "default" => 5
+        );
+        $tpls = self::generate('{block "%s"}%s{/block}', '{extends "level.%d.tpl"}');
+        foreach($tpls as $name => $tpl) {
             $this->tpl($name, $tpl["src"]);
             //var_dump($src, "----\n\n----", $dst);ob_flush();fgetc(STDIN);
-            $this->assertSame($this->cytro->fetch($name, array()), $tpl["dst"]);
+            $this->assertSame($this->cytro->fetch($name, $vars), $tpl["dst"]);
+        }
+        $tpls = self::generate('{block "{$%s}"}%s{/block}', '{extends "level.%d.tpl"}');
+        arsort($tpls);
+        foreach($tpls as $name => $tpl) {
+            $this->tpl("d.".$name, $tpl["src"]);
+            //var_dump($src, "----\n\n----", $dst);ob_flush();fgetc(STDIN);
+            $this->assertSame($this->cytro->fetch("d.".$name, $vars), $tpl["dst"]);
+            //var_dump($name);ob_flush();fgets(STDIN);
         }
     }