Reader mockup

src/Dataset.php

@@ -2,6 +2,8 @@
 
 namespace NoccyLabs\Dataset;
 
+use NoccyLabs\Dataset\Readers\CsvReader;
+use NoccyLabs\Dataset\Readers\JsonReader;
 
 class Dataset
 {
@@ -20,5 +22,25 @@ class Dataset
         return $this->identifier;
     }
 
+    public function open(): ReaderInterface
+    {
+        $filename = $this->options['filename'];
+        $reader = $this->determineReaderForFile($filename);
+        $inst = new $reader($filename, $this->options);
+        return $inst;
+    }
+
+    private function determineReaderForFile(string $filename): string
+    {
+        if ($reader = $this->options['reader']??null) {
+            return $reader;
+        }
+        $ext = pathinfo($filename, PATHINFO_EXTENSION);
+        return match ($ext) {
+            'json' => JsonReader::class,
+            'csv' => CsvReader::class,
+            default => throw new \RuntimeException("Unable to determine reader for dataset file")
+        };
+    }
     
 }