Add Reflection::package() utility method

Author: thekid

src/main/php/lang/Reflection.class.php

@@ -2,7 +2,7 @@
 
 use lang\meta\{MetaInformation, FromSyntaxTree, FromAttributes};
 use lang\reflection\{Type, Package};
-use lang\{ClassLoader, ClassNotFoundException};
+use lang\{ClassLoader, ClassNotFoundException, IllegalArgumentException};
 
 /**
  * Factory for reflection instances.
@@ -56,6 +56,22 @@ public static function type($arg) {
     }
   }
 
+  /**
+   * Returns a reflection package for a given argument.
+   *
+   * @param  string
+   * @return lang.reflection.Type
+   * @throws lang.IllegalArgumentException
+   */
+  public static function package($arg) {
+    $cl= ClassLoader::getDefault();
+    $name= strtr($arg, '\\', '.');
+    if ($cl->providesPackage($name)) {
+      return new Package($name);
+    }
+    throw new IllegalArgumentException('No package named '.$name);
+  }
+
   /**
    * Creates a new reflection instance, which may either refer to a type
    * or to a package.

src/test/php/lang/reflection/unittest/ReflectionTest.class.php

@@ -34,6 +34,11 @@ public function of_package_name() {
     Assert::instance(Package::class, Reflection::of('lang.reflection.unittest'));
   }
 
+  #[Test]
+  public function package() {
+    Assert::instance(Package::class, Reflection::package('lang.reflection.unittest'));
+  }
+
   #[Test, Values([70000, 70100, 70200, 70300, 70400])]
   public function parser_for_php7($versionId) {
     Assert::instance(FromSyntaxTree::class, Reflection::annotations($versionId));