updating the README.md

Author: andaniel05

README.md

@@ -1,6 +1,8 @@
 
 # MetaParser
 
+Extract metadata from attributes and/or annotations.
+
 #### If you like this project gift us a ⭐.
 
 <hr />
@@ -9,3 +11,66 @@
 
     composer require thenlabs/meta-parser dev-main
 
+## Usage example.
+
+```php
+/**
+ * @MyMetadata(data1="value1")
+ */
+#[MyMetadata(data1: 'value2')]
+class MyClass
+{
+}
+
+$myClass = new ReflectionClass(MyClass::class);
+
+/**
+ * Reading from annotations only.
+ */
+$annotationParser = new ThenLabs\MetaParser\AnnotationParser();
+$annotationParserResult = $annotationParser->parse($myClass);
+
+$annotationParserResult->get(MyMetadata::class)->get('data1') === 'value1'; // true
+
+/**
+ * Reading from attributes only.
+ */
+$attributeParser = new ThenLabs\MetaParser\AttributeParser();
+$attributeParserResult = $attributeParser->parse($myClass);
+
+$attributeParserResult->get(MyMetadata::class)->get('data1') === 'value2'; // true
+
+/**
+ * Reading both.
+ */
+$parser = new ThenLabs\MetaParser\Parser();
+$parserResult = $parser->parse($myClass);
+
+// this returns true becouse attributes override annotations.
+$parserResult->get(MyMetadata::class)->get('data1') === 'value2';
+```
+
+### Highlights about `ThenLabs\MetaParser\Parser` class.
+
+#### 1. For read annotations it's necessary to install [Doctrine Annotations](https://www.doctrine-project.org/projects/doctrine-annotations/en/1.13/index.html):
+
+    $ composer require doctrine/annotations
+
+#### 2. The attribute parser require a PHP version grater than 8.0.
+
+## Development.
+
+Clone this repository and install the Composer dependencies.
+
+    $ composer install
+
+### Running the tests.
+
+All the tests of this project was written with our testing framework [PyramidalTests][pyramidal-tests] wich is based on [PHPUnit][phpunit].
+
+Run tests:
+
+    $ composer test
+
+[phpunit]: https://phpunit.de
+[pyramidal-tests]: https://github.com/thenlabs/pyramidal-tests

src/Exception/NoParserFoundException.php

@@ -0,0 +1,11 @@
+<?php
+declare(strict_types=1);
+
+namespace ThenLabs\MetaParser\Exception;
+
+/**
+ * @author Andy Daniel Navarro Taño <[email protected]>
+ */
+class NoParserFoundException extends \Exception
+{
+}

src/Parser.php

@@ -5,6 +5,7 @@
 
 use Doctrine\Common\Annotations\AnnotationReader;
 use Reflector;
+use ThenLabs\MetaParser\Exception\NoParserFoundException;
 
 /**
  * @author Andy Daniel Navarro Taño <[email protected]>
@@ -37,8 +38,17 @@ public function setParsers(array $parsers): void
         $this->parsers = $parsers;
     }
 
+    /**
+     * @param Reflector $reflector
+     * @return Metadata
+     * @throws NoParserFoundException
+     */
     public function parse(Reflector $reflector): Metadata
     {
+        if (empty($this->parsers)) {
+            throw new NoParserFoundException();
+        }
+
         $result = [];
 
         foreach ($this->parsers as $parser) {

tests/test-Parser.php

@@ -1,5 +1,6 @@
 <?php
 
+use ThenLabs\MetaParser\Exception\NoParserFoundException;
 use ThenLabs\MetaParser\Parser;
 use ThenLabs\MetaParser\Tests\MyAnnotation;
 use ThenLabs\MetaParser\Tests\MyClass;
@@ -13,3 +14,12 @@
     $this->assertEquals($data1Expected, $result->get(MyAnnotation::class)->get('data1'));
     $this->assertNull($result->get(MyAnnotation::class)->get('data2'));
 });
+
+test(function () {
+    $this->expectException(NoParserFoundException::class);
+
+    $parser = new Parser();
+    $parser->setParsers([]);
+
+    $parser->parse(new ReflectionClass('stdClass'));
+});