Allow extensions to register serializers

Setting output_format must happen after extensions are loaded. Only in that
way can an extension register a serializer so that it will then be available
to be used with the output_format keyword. A test has been added to avoid
this regression from happening again in the future.

Fixes #238, partially reverses commit 41cc055 and provides a better fix for

3 files changed, 28 insertions, 8 deletions

diff --git a/markdown/__init__.py b/markdown/__init__.py
index 3fd5efa..275ed2e 100644
--- a/markdown/__init__.py
+++ b/markdown/__init__.py
@@ -133,9 +133,9 @@ class Markdown(object):
 
         self.references = {}
         self.htmlStash = util.HtmlStash()
-        self.set_output_format(kwargs.get('output_format', 'xhtml1'))
         self.registerExtensions(extensions=kwargs.get('extensions', []),
                                 configs=kwargs.get('extension_configs', {}))
+        self.set_output_format(kwargs.get('output_format', 'xhtml1'))
         self.reset()
 
     def build_parser(self):
diff --git a/markdown/extensions/footnotes.py b/markdown/extensions/footnotes.py
index 65ed597..9f93ad1 100644
--- a/markdown/extensions/footnotes.py
+++ b/markdown/extensions/footnotes.py
@@ -69,9 +69,6 @@ class FootnoteExtension(Extension):
         md.registerExtension(self)
         self.parser = md.parser
         self.md = md
-        self.sep = ':'
-        if self.md.output_format in ['html5', 'xhtml5']:
-            self.sep = '-'
         # Insert a preprocessor before ReferencePreprocessor
         md.preprocessors.add("footnote", FootnotePreprocessor(self),
                              "<reference")
@@ -113,19 +110,24 @@ class FootnoteExtension(Extension):
         """ Store a footnote for later retrieval. """
         self.footnotes[id] = text
 
+    def get_separator(self):
+        if self.md.output_format in ['html5', 'xhtml5']:
+            return '-'
+        return ':'
+
     def makeFootnoteId(self, id):
         """ Return footnote link id. """
         if self.getConfig("UNIQUE_IDS"):
-            return 'fn%s%d-%s' % (self.sep, self.unique_prefix, id)
+            return 'fn%s%d-%s' % (self.get_separator(), self.unique_prefix, id)
         else:
-            return 'fn%s%s' % (self.sep, id)
+            return 'fn%s%s' % (self.get_separator(), id)
 
     def makeFootnoteRefId(self, id):
         """ Return footnote back-link id. """
         if self.getConfig("UNIQUE_IDS"):
-            return 'fnref%s%d-%s' % (self.sep, self.unique_prefix, id)
+            return 'fnref%s%d-%s' % (self.get_separator(), self.unique_prefix, id)
         else:
-            return 'fnref%s%s' % (self.sep, id)
+            return 'fnref%s%s' % (self.get_separator(), id)
 
     def makeFootnotesDiv(self, root):
         """ Return div of footnotes as et Element. """
diff --git a/tests/test_apis.py b/tests/test_apis.py
index 4a7c7c7..bbe165d 100644
--- a/tests/test_apis.py
+++ b/tests/test_apis.py
@@ -358,6 +358,24 @@ class testSerializers(unittest.TestCase):
                     '<MixedCase>not valid <EMPHASIS>html</EMPHASIS><HR /></MixedCase>')
 
 
+    def buildExtension(self):
+        """ Build an extension which registers fakeSerializer. """
+        def fakeSerializer(elem):
+            # Ignore input and return hardcoded output
+            return '<div><p>foo</p></div>'
+
+        class registerFakeSerializer(markdown.extensions.Extension):
+            def extendMarkdown(self, md, md_globals):
+                md.output_formats['fake'] = fakeSerializer
+
+        return registerFakeSerializer()
+
+    def testRegisterSerializer(self):
+        self.assertEqual(markdown.markdown('baz', 
+                extensions=[self.buildExtension()], output_format='fake'),
+                    '<p>foo</p>')
+
+
 class testAtomicString(unittest.TestCase):
     """ Test that AtomicStrings are honored (not parsed). """