doc/lib: Add DocToc class representing a toc

refs #4820

modules/doc/library/Doc/DocToc.php

@@ -0,0 +1,48 @@
+<?php
+// {{{ICINGA_LICENSE_HEADER}}}
+// {{{ICINGA_LICENSE_HEADER}}}
+
+namespace Icinga\Module\Doc;
+
+use IteratorAggregate;
+use Icinga\Data\Tree\NodeInterface;
+use Icinga\Data\Tree\TreeIterator;
+
+class DocToc implements NodeInterface, IteratorAggregate
+{
+    protected $children = array();
+
+    protected $value;
+
+    public function __construct($value = null)
+    {
+        $this->value = $value;
+    }
+
+    public function getValue()
+    {
+        return $this->value;
+    }
+
+    public function appendChild($value)
+    {
+        $child = new self($value);
+        $this->children[] = $child;
+        return $child;
+    }
+
+    public function hasChildren()
+    {
+        return ! empty($this->children);
+    }
+
+    public function getChildren()
+    {
+        return $this->children;
+    }
+
+    public function getIterator()
+    {
+        return new TreeIterator($this);
+    }
+}