Start on serializer

lib/Parser/Serializer.php

@@ -0,0 +1,34 @@
+<?php
+/** @license MIT
+ * Copyright 2017 , Dustin Wilson, J. King et al.
+ * See LICENSE and AUTHORS files for details */
+
+declare(strict_types=1);
+namespace MensBeam\HTML\Parser;
+
+use MensBeam\HTML\Parser;
+
+abstract class Serializer {
+    protected const VOID_ELEMENTS = ["basefont", "bgsound", "frame", "keygen", "area", "base", "br", "col", "embed", "hr", "img", "input", "link", "meta", "param", "source", "track", "wbr"];
+
+    public function seerializeOuter(\DOMNode $node): string {
+        $s = "";
+        $depth = 0;
+        $n = $node;
+        do {
+            # If current node is an Element
+            if ($n instanceof \DOMElement) {
+                # If current node is an element in the HTML namespace,
+                #   the MathML namespace, or the SVG namespace, then let
+                #   tagname be current node's local name. Otherwise, let
+                #   tagname be current node's qualified name.
+                if (in_array($n->namespaceURI ?? Parser::HTML_NAMESPACE, [Parser::HTML_NAMESPACE, Parser::SVG_NAMESPACE, Parser::MATHML_NAMESPACE])) {
+                    $tagName = $n->localName;
+                } else {
+                    $tagName = $n->tagName;
+                }
+            }
+        } while (false);
+        return $s;
+    }
+}