html_attribute: "serializers.RE_AMP" を弄って試行錯誤

html_attribute.py

@@ -9,6 +9,7 @@
 
 import markdown
 from markdown import postprocessors
+from markdown import serializers
 
 import xml.etree.ElementTree as etree
 
@@ -312,6 +313,17 @@ def _add_meta(self, element):
                 element.remove(e)
         element.append(body)
 
+    def _tohtml(self, element):
+        # return etree.tostring(root, encoding="unicode", method="xml")
+        # return etree.tostring(root, encoding="unicode", method="html")
+        old_RE_AMP = serializers.RE_AMP
+        try:
+            serializers.RE_AMP = re.compile(r'&')
+            output = self._markdown.serializer(element)
+        finally:
+            serializers.RE_AMP = old_RE_AMP
+        return output
+
     def run(self, text):
         text = '<{tag}>{text}</{tag}>'.format(tag=self._markdown.doc_tag, text=text)
         try:
@@ -328,7 +340,7 @@ def run(self, text):
         self._iterate(root, self._adjust_url)
         self._add_meta(root)
 
-        output = etree.tostring(root, encoding="unicode", method="xml")
+        output = self._tohtml(root)
         if self._markdown.stripTopLevelTags:
             try:
                 start = output.index('<%s>' % self._markdown.doc_tag) + len(self._markdown.doc_tag) + 2