Add some useful renderables

src/Html/Renderables/Container.php

@@ -0,0 +1,47 @@
+<?php
+
+namespace Erusev\Parsedown\Html\Renderables;
+
+use Erusev\Parsedown\Html\Renderable;
+
+final class Container implements Renderable
+{
+    use CanonicalStateRenderable;
+
+    /** @var Renderable[] */
+    private $Contents;
+
+    /**
+     * @param Renderable[] $Contents
+     */
+    public function __construct($Contents)
+    {
+        $this->Contents = $Contents;
+    }
+
+    /**
+     * @return Renderable[]
+     */
+    public function contents()
+    {
+        return $this->Contents;
+    }
+
+
+    /** @return string */
+    public function getHtml()
+    {
+        return \array_reduce(
+            $this->Contents,
+            /**
+             * @param string $html
+             * @param Renderable $Renderable
+             * @return string
+             */
+            function ($html, Renderable $Renderable) {
+                return $html . $Renderable->getHtml();
+            },
+            ''
+        );
+    }
+}

src/Html/Renderables/Invisible.php

@@ -0,0 +1,20 @@
+<?php
+
+namespace Erusev\Parsedown\Html\Renderables;
+
+use Erusev\Parsedown\Html\Renderable;
+
+final class Invisible implements Renderable
+{
+    use CanonicalStateRenderable;
+
+    public function __construct()
+    {
+    }
+
+    /** @return string */
+    public function getHtml()
+    {
+        return '';
+    }
+}

src/Html/Renderables/RawHtml.php

@@ -0,0 +1,27 @@
+<?php
+
+namespace Erusev\Parsedown\Html\Renderables;
+
+use Erusev\Parsedown\Html\Renderable;
+
+final class RawHtml implements Renderable
+{
+    use CanonicalStateRenderable;
+
+    /** @var string */
+    private $html;
+
+    /**
+     * @param string $html
+     */
+    public function __construct($html = '')
+    {
+        $this->html = $html;
+    }
+
+    /** @return string */
+    public function getHtml()
+    {
+        return $this->html;
+    }
+}