feat: first impl

src/Stdio.php

@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Nih\CommandBuilder;
+
+use Stringable;
+
+abstract class Stdio
+{
+    abstract public function getDescriptorSpec(): array;
+
+    public static function file(string|Stringable $file, string $mode): self
+    {
+        return new StdioFile((string) $file, $mode);
+    }
+
+    public static function piped(string $mode): self
+    {
+        return new StdioPiped($mode);
+    }
+
+    public static function inherit(): null
+    {
+        return null;
+    }
+
+    public static function null(): self
+    {
+        return new StdioFile('/dev/null', 'a+');
+    }
+}