5 files changed, 40 insertions, 58 deletions
diff --git a/markdown/core.py b/markdown/core.py
index 2144f00..d25f20d 100644
--- a/markdown/core.py
+++ b/markdown/core.py
@@ -47,11 +47,6 @@ class Markdown(object):
 
     doc_tag = "div"     # Element used to wrap document - later removed
 
-    option_defaults = {
-        'tab_length':            4,
-        'smart_emphasis':        True,
-    }
-
     output_formats = {
         'html':   to_html_string,
         'xhtml':  to_xhtml_string,
@@ -73,13 +68,10 @@ class Markdown(object):
             * "xhtml": Outputs XHTML style tags. Default.
             * "html": Outputs HTML style tags.
         * tab_length: Length of tabs in the source. Default: 4
-        * smart_emphasis: Treat `_connected_words_` intelligently Default: True
 
         """
 
-        # Loop through kwargs and assign defaults
-        for option, default in self.option_defaults.items():
-            setattr(self, option, kwargs.get(option, default))
+        self.tab_length = kwargs.get('tab_length', 4)
 
         self.ESCAPED_CHARS = ['\\', '`', '*', '_', '{', '}', '[', ']',
                               '(', ')', '>', '#', '+', '-', '.', '!']
diff --git a/markdown/extensions/extra.py b/markdown/extensions/extra.py
index 19b9db0..e498a74 100644
--- a/markdown/extensions/extra.py
+++ b/markdown/extensions/extra.py
@@ -37,7 +37,6 @@ from .. import util
 import re
 
 extensions = [
-    'smart_strong',
     'fenced_code',
     'footnotes',
     'attr_list',
diff --git a/markdown/extensions/legacy_em.py b/markdown/extensions/legacy_em.py
new file mode 100644
index 0000000..5cc0f6d
--- /dev/null
+++ b/markdown/extensions/legacy_em.py
@@ -0,0 +1,30 @@
+'''
+Legacy Em Extension for Python-Markdown
+=======================================
+
+This extention provides legacy behavior for _connected_words_.
+
+Copyright 2015-2018 The Python Markdown Project
+
+License: [BSD](http://www.opensource.org/licenses/bsd-license.php)
+
+'''
+
+from __future__ import absolute_import
+from __future__ import unicode_literals
+from . import Extension
+from ..inlinepatterns import SimpleTagInlineProcessor
+
+EMPHASIS_RE = r'(\*|_)(.+?)\1'
+STRONG_RE = r'(\*{2}|_{2})(.+?)\1'
+
+
+class LegacyEmExtension(Extension):
+    """ Add legacy_em extension to Markdown class."""
+
+    def extendMarkdown(self, md, md_globals):
+        """ Modify inline patterns. """
+        md.inlinePatterns.register(SimpleTagInlineProcessor(STRONG_RE, 'strong'), 'strong', 40)
+        md.inlinePatterns.register(SimpleTagInlineProcessor(EMPHASIS_RE, 'em'), 'emphasis', 30)
+        md.inlinePatterns.deregister('strong2')
+        md.inlinePatterns.deregister('emphasis2')
diff --git a/markdown/extensions/smart_strong.py b/markdown/extensions/smart_strong.py
deleted file mode 100644
index e7a15d9..0000000
--- a/markdown/extensions/smart_strong.py
+++ /dev/null
@@ -1,37 +0,0 @@
-'''
-Smart_Strong Extension for Python-Markdown
-==========================================
-
-This extension adds smarter handling of double underscores within words.
-
-See <https://Python-Markdown.github.io/extensions/smart_strong>
-for documentation.
-
-Original code Copyright 2011 [Waylan Limberg](http://achinghead.com)
-
-All changes Copyright 2011-2014 The Python Markdown Project
-
-License: [BSD](http://www.opensource.org/licenses/bsd-license.php)
-
-'''
-
-from __future__ import absolute_import
-from __future__ import unicode_literals
-from . import Extension
-from ..inlinepatterns import SimpleTagInlineProcessor
-
-SMART_STRONG_RE = r'(?<!\w)(_{2})(?!_)(.+?)(?<!_)\1(?!\w)'
-STRONG_RE = r'(\*{2})(.+?)\1'
-
-
-class SmartEmphasisExtension(Extension):
-    """ Add smart_emphasis extension to Markdown class."""
-
-    def extendMarkdown(self, md, md_globals):
-        """ Modify inline patterns. """
-        md.inlinePatterns.register(SimpleTagInlineProcessor(STRONG_RE, 'strong'), 'strong', 40)
-        md.inlinePatterns.register(SimpleTagInlineProcessor(SMART_STRONG_RE, 'strong'), 'strong2', 10)
-
-
-def makeExtension(**kwargs):  # pragma: no cover
-    return SmartEmphasisExtension(**kwargs)
diff --git a/markdown/inlinepatterns.py b/markdown/inlinepatterns.py
index 8d49d07..e4af53e 100644
--- a/markdown/inlinepatterns.py
+++ b/markdown/inlinepatterns.py
@@ -95,10 +95,8 @@ def build_inlinepatterns(md, **kwargs):
     inlinePatterns.register(DoubleTagInlineProcessor(STRONG_EM_RE, 'em,strong'), 'strong_em', 50)
     inlinePatterns.register(SimpleTagInlineProcessor(STRONG_RE, 'strong'), 'strong', 40)
     inlinePatterns.register(SimpleTagInlineProcessor(EMPHASIS_RE, 'em'), 'emphasis', 30)
-    if md.smart_emphasis:
-        inlinePatterns.register(SimpleTagInlineProcessor(SMART_EMPHASIS_RE, 'em'), 'emphasis2', 20)
-    else:
-        inlinePatterns.register(SimpleTagInlineProcessor(EMPHASIS_2_RE, 'em'), 'emphasis2', 20)
+    inlinePatterns.register(SimpleTagInlineProcessor(SMART_STRONG_RE, 'strong'), 'strong2', 20)
+    inlinePatterns.register(SimpleTagInlineProcessor(SMART_EMPHASIS_RE, 'em'), 'emphasis2', 10)
     return inlinePatterns
 
 
@@ -119,7 +117,13 @@ ESCAPE_RE = r'\\(.)'
 EMPHASIS_RE = r'(\*)([^\*]+)\1'
 
 # **strong**
-STRONG_RE = r'(\*{2}|_{2})(.+?)\1'
+STRONG_RE = r'(\*{2})(.+?)\1'
+
+# __smart__strong__
+SMART_STRONG_RE = r'(?<!\w)(_{2})(?!_)(.+?)(?<!_)\1(?!\w)'
+
+# _smart_emphasis_
+SMART_EMPHASIS_RE = r'(?<!\w)(_)(?!_)(.+?)(?<!_)\1(?!\w)'
 
 # ***strongem*** or ***em*strong**
 EM_STRONG_RE = r'(\*|_)\1{2}(.+?)\1(.*?)\1{2}'
@@ -127,12 +131,6 @@ EM_STRONG_RE = r'(\*|_)\1{2}(.+?)\1(.*?)\1{2}'
 # ***strong**em*
 STRONG_EM_RE = r'(\*|_)\1{2}(.+?)\1{2}(.*?)\1'
 
-# _smart_emphasis_
-SMART_EMPHASIS_RE = r'(?<!\w)(_)(?!_)(.+?)(?<!_)\1(?!\w)'
-
-# _emphasis_
-EMPHASIS_2_RE = r'(_)(.+?)\1'
-
 # [text](url) or [text](<url>) or [text](url "title")
 LINK_RE = NOIMG + r'\['