Improve return type of get* functions, closes #21

src/Input.php

@@ -107,8 +107,9 @@ public function add(string $key, InputDatum $datum, string $method):void {
 	 * Get a particular input value by its key. To specify either GET or POST variables, pass
 	 * Input::METHOD_GET or Input::METHOD_POST as the second parameter (defaults to
 	 * Input::METHOD_BOTH).
+	 * @return mixed|null
 	 */
-	public function get(string $key, string $method = null):?InputDatum {
+	public function get(string $key, string $method = null) {
 		if(is_null($method)) {
 			$method = self::DATA_COMBINED;
 		}

src/InputData/AbstractInputData.php

@@ -14,7 +14,8 @@ abstract class AbstractInputData implements ArrayAccess, Countable, Iterator {
 	/** @var InputDatum[] */
 	protected $parameters = [];
 
-	public function get(string $key):?InputDatum {
+	/** @return mixed|null */
+	public function get(string $key) {
 		return $this->parameters[$key] ?? null;
 	}
 

src/InputData/FileUploadInputData.php

@@ -8,8 +8,6 @@ class FileUploadInputData extends InputData {
 
 	public function __construct(array $files) {
 		$files = $this->normalizeArray($files);
-
-		// TODO: Set $this->parameters with kvp of files ($files[filename] => FileUpload(data))
 		$data = $this->createData($files);
 		parent::__construct($data);
 	}

src/InputData/KeyValueArrayAccess.php

@@ -1,15 +1,26 @@
 <?php
 namespace Gt\Input\InputData;
 
+use Gt\Input\Input;
 use Gt\Input\InputData\Datum\InputDatum;
 
 trait KeyValueArrayAccess {
 	public function offsetExists($offset):bool {
 		return isset($this->parameters[$offset]);
 	}
 
-	public function offsetGet($offset):?InputDatum {
-		return $this->get($offset);
+	/** @return mixed|null */
+	public function offsetGet($offset) {
+		if($this instanceof FileUploadInputData) {
+			return $this->getFile($offset);
+		}
+		elseif($this instanceof Input || $this instanceof InputData) {
+			if($this->contains($offset)) {
+				return $this->get($offset);
+			}
+		}
+
+		return null;
 	}
 
 	public function offsetSet($offset, $value):void {

src/InputValueGetter.php

@@ -4,7 +4,9 @@
 use DateTime;
 use DateTimeInterface;
 use Exception;
+use Gt\Input\InputData\CombinedInputData;
 use Gt\Input\InputData\Datum\FileUpload;
+use Gt\Input\InputData\Datum\InputDatum;
 use Gt\Input\InputData\Datum\MultipleInputDatum;
 use Gt\Input\InputData\FileUploadInputData;
 use TypeError;
@@ -42,12 +44,18 @@ public function getBool(string $key):?bool {
 	}
 
 	public function getFile(string $key):FileUpload {
+		/** @var FileUploadInputData|InputDatum[] $params */
 		$params = $this->fileUploadParameters ?? $this->parameters;
 
 		try {
-			/** @var MultipleInputDatum $datum */
-			$datum = $params[$key];
-			return $datum->current();
+			/** @var MultipleInputDatum|FileUpload $file */
+			$file = $params[$key];
+
+			if($file instanceof MultipleInputDatum) {
+				return $file->current();
+			}
+
+			return $file;
 		}
 		catch(TypeError $exception) {
 			throw new DataNotFileUploadException($key);

test/unit/InputTest.php

@@ -90,9 +90,7 @@ public function testGetPostField(array $get, array $post):void {
 	public function testGetFileFieldSingle(array $get, array $post):void {
 		$files = self::FAKE_FILE;
 		$input = new Input($get, $post, $files);
-		$file = $input->get("exampleFile", Input::DATA_FILES);
-
-		/** @var FileUpload $file */
+		$file = $input->getFile("exampleFile");
 
 		self::assertInstanceOf(
 			FileUpload::class,