text: #!/usr/bin/env python
  # Copyright (c) 2012 Trent Mick.
  # Copyright (c) 2007-2008 ActiveState Corp.
  # License: MIT (http://www.opensource.org/licenses/mit-license.php)
  
  from __future__ import generators
  
  r"""A fast and complete Python implementation of Markdown.
  
  [from http://daringfireball.net/projects/markdown/]
  > Markdown is a text-to-HTML filter; it translates an easy-to-read /
  > easy-to-write structured text format into HTML.  Markdown's text
  > format is most similar to that of plain text email, and supports
  > features such as headers, *emphasis*, code blocks, blockquotes, and
  > links.
  >
  > Markdown's syntax is designed not as a generic markup language, but
  > specifically to serve as a front-end to (X)HTML. You can use span-level
  > HTML tags anywhere in a Markdown document, and you can use block level
  > HTML tags (like <div> and <table> as well).
  
  Module usage:
  
      >>> import markdown2
      >>> markdown2.markdown("*boo!*")  # or use `html = markdown_path(PATH)`
      u'<p><em>boo!</em></p>\n'
  
      >>> markdowner = Markdown()
      >>> markdowner.convert("*boo!*")
      u'<p><em>boo!</em></p>\n'
      >>> markdowner.convert("**boom!**")
      u'<p><strong>boom!</strong></p>\n'
  
  This implementation of Markdown implements the full "core" syntax plus a
  number of extras (e.g., code syntax coloring, footnotes) as described on
  <https://github.com/trentm/python-markdown2/wiki/Extras>.
  """
  
  cmdln_desc = """A fast and complete Python implementation of Markdown, a
  text-to-HTML conversion tool for web writers.
  
  Supported extra syntax options (see -x|--extras option below and
  see <https://github.com/trentm/python-markdown2/wiki/Extras> for details):
  
  * code-friendly: Disable _ and __ for em and strong.
  * cuddled-lists: Allow lists to be cuddled to the preceding paragraph.
  * fenced-code-blocks: Allows a code block to not have to be indented
    by fencing it with '```' on a line before and after. Based on
    <http://github.github.com/github-flavored-markdown/> with support for
    syntax highlighting.
  * footnotes: Support footnotes as in use on daringfireball.net and
    implemented in other Markdown processors (tho not in Markdown.pl v1.0.1).
  * header-ids: Adds "id" attributes to headers. The id value is a slug of
    the header text.
  * html-classes: Takes a dict mapping html tag names (lowercase) to a
    string to use for a "class" tag attribute. Currently only supports
    "pre" and "code" tags. Add an issue if you require this for other tags.
  * markdown-in-html: Allow the use of `markdown="1"` in a block HTML tag to
    have markdown processing be done on its contents. Similar to
    <http://michelf.com/projects/php-markdown/extra/#markdown-attr> but with
    some limitations.
  * metadata: Extract metadata from a leading '---'-fenced block.
    See <https://github.com/trentm/python-markdown2/issues/77> for details.
  * nofollow: Add `rel="nofollow"` to add `<a>` tags with an href. See
    <http://en.wikipedia.org/wiki/Nofollow>.
  * pyshell: Treats unindented Python interactive shell sessions as <code>
    blocks.
  * link-patterns: Auto-link given regex patterns in text (e.g. bug number
    references, revision number references).
  * smarty-pants: Replaces ' and " with curly quotation marks or curly
    apostrophes.  Replaces --, ---, ..., and . . . with en dashes, em dashes,
    and ellipses.
  * toc: The returned HTML string gets a new "toc_html" attribute which is
    a Table of Contents for the document. (experimental)
  * xml: Passes one-liner processing instructions and namespaced XML tags.
  * wiki-tables: Google Code Wiki-style tables. See
    <http://code.google.com/p/support/wiki/WikiSyntax#Tables>.
  """
  
  # Dev Notes:
  # - Python's regex syntax doesn't have '\z', so I'm using '\Z'. I'm
  #   not yet sure if there implications with this. Compare 'pydoc sre'
  #   and 'perldoc perlre'.
  
  __version_info__ = (2, 1, 1)
  __version__ = '.'.join(map(str, __version_info__))
  __author__ = "Trent Mick"
  
  import os
  import sys
  from pprint import pprint
  import re
  import logging
  try:
      from hashlib import md5
  except ImportError:
      from md5 import md5
  import optparse
  from random import random, randint
  import codecs
  
  
  #---- Python version compat
  
  try:
      from urllib.parse import quote # python3
  except ImportError:
      from urllib import quote # python2
  
  if sys.version_info[:2] < (2,4):
      from sets import Set as set
      def reversed(sequence):
          for i in sequence[::-1]:
              yield i
  
  # Use `bytes` for byte strings and `unicode` for unicode strings (str in Py3).
  if sys.version_info[0] <= 2:
      py3 = False
      try:
          bytes
      except NameError:
          bytes = str
      base_string_type = basestring
  elif sys.version_info[0] >= 3:
      py3 = True
      unicode = str
      base_string_type = str
  
  
  
  #---- globals
  
  DEBUG = False
  log = logging.getLogger("markdown")
  
  DEFAULT_TAB_WIDTH = 4
  
  
  SECRET_SALT = bytes(randint(0, 1000000))
  def _hash_text(s):
      return 'md5-' + md5(SECRET_SALT + s.encode("utf-8")).hexdigest()
  
  # Table of hash values for escaped characters:
  g_escape_table = dict([(ch, _hash_text(ch))
      for ch in '\\`*_{}[]()>#+-.!'])
  
  
  
  #---- exceptions
  
  class MarkdownError(Exception):
      pass
  
  
  
  #---- public api
  
  def markdown_path(path, encoding="utf-8",
                    html4tags=False, tab_width=DEFAULT_TAB_WIDTH,
                    safe_mode=None, extras=None, link_patterns=None,
                    use_file_vars=False):
      fp = codecs.open(path, 'r', encoding)
      text = fp.read()
      fp.close()
      return Markdown(html4tags=html4tags, tab_width=tab_width,
                      safe_mode=safe_mode, extras=extras,
                      link_patterns=link_patterns,
                      use_file_vars=use_file_vars).convert(text)
  
  def markdown(text, html4tags=False, tab_width=DEFAULT_TAB_WIDTH,
               safe_mode=None, extras=None, link_patterns=None,
               use_file_vars=False):
      return Markdown(html4tags=html4tags, tab_width=tab_width,
                      safe_mode=safe_mode, extras=extras,
                      link_patterns=link_patterns,
                      use_file_vars=use_file_vars).convert(text)
  
  class Markdown(object):
      # The dict of "extras" to enable in processing -- a mapping of
      # extra name to argument for the extra. Most extras do not have an
      # argument, in which case the value is None.
      #
      # This can be set via (a) subclassing and (b) the constructor
      # "extras" argument.
      extras = None
  
      urls = None
      titles = None
      html_blocks = None
      html_spans = None
      html_removed_text = "[HTML_REMOVED]"  # for compat with markdown.py
  
      # Used to track when we're inside an ordered or unordered list
      # (see _ProcessListItems() for details):
      list_level = 0
  
      _ws_only_line_re = re.compile(r"^[ \t]+$", re.M)
  
      def __init__(self, html4tags=False, tab_width=4, safe_mode=None,
                   extras=None, link_patterns=None, use_file_vars=False):
          if html4tags:
              self.empty_element_suffix = ">"
          else:
              self.empty_element_suffix = " />"
          self.tab_width = tab_width
  
          # For compatibility with earlier markdown2.py and with
          # markdown.py's safe_mode being a boolean,
          #   safe_mode == True -> "replace"
          if safe_mode is True:
              self.safe_mode = "replace"
          else:
              self.safe_mode = safe_mode
  
          # Massaging and building the "extras" info.
          if self.extras is None:
              self.extras = {}
          elif not isinstance(self.extras, dict):
              self.extras = dict([(e, None) for e in self.extras])
          if extras:
              if not isinstance(extras, dict):
                  extras = dict([(e, None) for e in extras])
              self.extras.update(extras)
          assert isinstance(self.extras, dict)
          if "toc" in self.extras and not "header-ids" in self.extras:
              self.extras["header-ids"] = None   # "toc" implies "header-ids"
          self._instance_extras = self.extras.copy()
  
          self.link_patterns = link_patterns
          self.use_file_vars = use_file_vars
          self._outdent_re = re.compile(r'^(\t|[ ]{1,%d})' % tab_width, re.M)
  
          self._escape_table = g_escape_table.copy()
          if "smarty-pants" in self.extras:
              self._escape_table['"'] = _hash_text('"')
              self._escape_table["'"] = _hash_text("'")
  
      def reset(self):
          self.urls = {}
          self.titles = {}
          self.html_blocks = {}
          self.html_spans = {}
          self.list_level = 0
          self.extras = self._instance_extras.copy()
          if "footnotes" in self.extras:
              self.footnotes = {}
              self.footnote_ids = []
          if "header-ids" in self.extras:
              self._count_from_header_id = {} # no `defaultdict` in Python 2.4
          if "metadata" in self.extras:
              self.metadata = {}
  
      # Per <https://developer.mozilla.org/en-US/docs/HTML/Element/a> "rel"
      # should only be used in <a> tags with an "href" attribute.
      _a_nofollow = re.compile(r"<(a)([^>]*href=)", re.IGNORECASE)
  
      def convert(self, text):
          """Convert the given text."""
          # Main function. The order in which other subs are called here is
          # essential. Link and image substitutions need to happen before
          # _EscapeSpecialChars(), so that any *'s or _'s in the <a>
          # and <img> tags get encoded.
  
          # Clear the global hashes. If we don't clear these, you get conflicts
          # from other articles when generating a page which contains more than
          # one article (e.g. an index page that shows the N most recent
          # articles):
          self.reset()
  
          if not isinstance(text, unicode):
              #TODO: perhaps shouldn't presume UTF-8 for string input?
              text = unicode(text, 'utf-8')
  
          if self.use_file_vars:
              # Look for emacs-style file variable hints.
              emacs_vars = self._get_emacs_vars(text)
              if "markdown-extras" in emacs_vars:
                  splitter = re.compile("[ ,]+")
                  for e in splitter.split(emacs_vars["markdown-extras"]):
                      if '=' in e:
                          ename, earg = e.split('=', 1)
                          try:
                              earg = int(earg)
                          except ValueError:
                              pass
                      else:
                          ename, earg = e, None
                      self.extras[ename] = earg
  
          # Standardize line endings:
          text = re.sub("\r\n|\r", "\n", text)
  
          # Make sure $text ends with a couple of newlines:
          text += "\n\n"
  
          # Convert all tabs to spaces.
          text = self._detab(text)
  
          # Strip any lines consisting only of spaces and tabs.
          # This makes subsequent regexen easier to write, because we can
          # match consecutive blank lines with /\n+/ instead of something
          # contorted like /[ \t]*\n+/ .
          text = self._ws_only_line_re.sub("", text)
  
          # strip metadata from head and extract
          if "metadata" in self.extras:
              text = self._extract_metadata(text)
  
          text = self.preprocess(text)
  
          if self.safe_mode:
              text = self._hash_html_spans(text)
  
          # Turn block-level HTML blocks into hash entries
          text = self._hash_html_blocks(text, raw=True)
  
          # Strip link definitions, store in hashes.
          if "footnotes" in self.extras:
              # Must do footnotes first because an unlucky footnote defn
              # looks like a link defn:
              #   [^4]: this "looks like a link defn"
              text = self._strip_footnote_definitions(text)
          text = self._strip_link_definitions(text)
  
          text = self._run_block_gamut(text)
  
          if "footnotes" in self.extras:
              text = self._add_footnotes(text)
  
          text = self.postprocess(text)
  
          text = self._unescape_special_chars(text)
  
          if self.safe_mode:
              text = self._unhash_html_spans(text)
  
          if "nofollow" in self.extras:
              text = self._a_nofollow.sub(r'<\1 rel="nofollow"\2', text)
  
          text += "\n"
  
          rv = UnicodeWithAttrs(text)
          if "toc" in self.extras:
              rv._toc = self._toc
          if "metadata" in self.extras:
              rv.metadata = self.metadata
          return rv
  
      def postprocess(self, text):
          """A hook for subclasses to do some postprocessing of the html, if
          desired. This is called before unescaping of special chars and
          unhashing of raw HTML spans.
          """
          return text
  
      def preprocess(self, text):
          """A hook for subclasses to do some preprocessing of the Markdown, if
          desired. This is called after basic formatting of the text, but prior
          to any extras, safe mode, etc. processing.
          """
          return text
  
      # Is metadata if the content starts with '---'-fenced `key: value`
      # pairs. E.g. (indented for presentation):
      #   ---
      #   foo: bar
      #   another-var: blah blah
      #   ---
      _metadata_pat = re.compile("""^---[ \t]*\n((?:[ \t]*[^ \t:]+[ \t]*:[^\n]*\n)+)---[ \t]*\n""")
  
      def _extract_metadata(self, text):
          # fast test
          if not text.startswith("---"):
              return text
          match = self._metadata_pat.match(text)
          if not match:
              return text
  
          tail = text[len(match.group(0)):]
          metadata_str = match.group(1).strip()
          for line in metadata_str.split('\n'):
              key, value = line.split(':', 1)
              self.metadata[key.strip()] = value.strip()
  
          return tail
  
  
      _emacs_oneliner_vars_pat = re.compile(r"-\*-\s*([^\r\n]*?)\s*-\*-", re.UNICODE)
      # This regular expression is intended to match blocks like this:
      #    PREFIX Local Variables: SUFFIX
      #    PREFIX mode: Tcl SUFFIX
      #    PREFIX End: SUFFIX
      # Some notes:
      # - "[ \t]" is used instead of "\s" to specifically exclude newlines
      # - "(\r\n|\n|\r)" is used instead of "$" because the sre engine does
      #   not like anything other than Unix-style line terminators.
      _emacs_local_vars_pat = re.compile(r"""^
          (?P<prefix>(?:[^\r\n|\n|\r])*?)
          [\ \t]*Local\ Variables:[\ \t]*
          (?P<suffix>.*?)(?:\r\n|\n|\r)
          (?P<content>.*?\1End:)
          """, re.IGNORECASE | re.MULTILINE | re.DOTALL | re.VERBOSE)
  
      def _get_emacs_vars(self, text):
          """Return a dictionary of emacs-style local variables.
  
          Parsing is done loosely according to this spec (and according to
          some in-practice deviations from this):
          http://www.gnu.org/software/emacs/manual/html_node/emacs/Specifying-File-Variables.html#Specifying-File-Variables
          """
          emacs_vars = {}
          SIZE = pow(2, 13) # 8kB
  
          # Search near the start for a '-*-'-style one-liner of variables.
          head = text[:SIZE]
          if "-*-" in head:
              match = self._emacs_oneliner_vars_pat.search(head)
              if match:
                  emacs_vars_str = match.group(1)
                  assert '\n' not in emacs_vars_str
                  emacs_var_strs = [s.strip() for s in emacs_vars_str.split(';')
                                    if s.strip()]
                  if len(emacs_var_strs) == 1 and ':' not in emacs_var_strs[0]:
                      # While not in the spec, this form is allowed by emacs:
                      #   -*- Tcl -*-
                      # where the implied "variable" is "mode". This form
                      # is only allowed if there are no other variables.
                      emacs_vars["mode"] = emacs_var_strs[0].strip()
                  else:
                      for emacs_var_str in emacs_var_strs:
                          try:
                              variable, value = emacs_var_str.strip().split(':', 1)
                          except ValueError:
                              log.debug("emacs variables error: malformed -*- "
                                        "line: %r", emacs_var_str)
                              continue
                          # Lowercase the variable name because Emacs allows "Mode"
                          # or "mode" or "MoDe", etc.
                          emacs_vars[variable.lower()] = value.strip()
  
          tail = text[-SIZE:]
          if "Local Variables" in tail:
              match = self._emacs_local_vars_pat.search(tail)
              if match:
                  prefix = match.group("prefix")
                  suffix = match.group("suffix")
                  lines = match.group("content").splitlines(0)
                  #print "prefix=%r, suffix=%r, content=%r, lines: %s"\
                  #      % (prefix, suffix, match.group("content"), lines)
  
                  # Validate the Local Variables block: proper prefix and suffix
                  # usage.
                  for i, line in enumerate(lines):
                      if not line.startswith(prefix):
                          log.debug("emacs variables error: line '%s' "
                                    "does not use proper prefix '%s'"
                                    % (line, prefix))
                          return {}
                      # Don't validate suffix on last line. Emacs doesn't care,
                      # neither should we.
                      if i != len(lines)-1 and not line.endswith(suffix):
                          log.debug("emacs variables error: line '%s' "
                                    "does not use proper suffix '%s'"
                                    % (line, suffix))
                          return {}
  
                  # Parse out one emacs var per line.
                  continued_for = None
                  for line in lines[:-1]: # no var on the last line ("PREFIX End:")
                      if prefix: line = line[len(prefix):] # strip prefix
                      if suffix: line = line[:-len(suffix)] # strip suffix
                      line = line.strip()
                      if continued_for:
                          variable = continued_for
                          if line.endswith('\\'):
                              line = line[:-1].rstrip()
                          else:
                              continued_for = None
                          emacs_vars[variable] += ' ' + line
                      else:
                          try:
                              variable, value = line.split(':', 1)
                          except ValueError:
                              log.debug("local variables error: missing colon "
                                        "in local variables entry: '%s'" % line)
                              continue
                          # Do NOT lowercase the variable name, because Emacs only
                          # allows "mode" (and not "Mode", "MoDe", etc.) in this block.
                          value = value.strip()
                          if value.endswith('\\'):
                              value = value[:-1].rstrip()
                              continued_for = variable
                          else:
                              continued_for = None
                          emacs_vars[variable] = value
  
          # Unquote values.
          for var, val in list(emacs_vars.items()):
              if len(val) > 1 and (val.startswith('"') and val.endswith('"')
                 or val.startswith('"') and val.endswith('"')):
                  emacs_vars[var] = val[1:-1]
  
          return emacs_vars
  
      # Cribbed from a post by Bart Lateur:
      # <http://www.nntp.perl.org/group/perl.macperl.anyperl/154>
      _detab_re = re.compile(r'(.*?)\t', re.M)
      def _detab_sub(self, match):
          g1 = match.group(1)
          return g1 + (' ' * (self.tab_width - len(g1) % self.tab_width))
      def _detab(self, text):
          r"""Remove (leading?) tabs from a file.
  
              >>> m = Markdown()
              >>> m._detab("\tfoo")
              '    foo'
              >>> m._detab("  \tfoo")
              '    foo'
              >>> m._detab("\t  foo")
              '      foo'
              >>> m._detab("  foo")
              '  foo'
              >>> m._detab("  foo\n\tbar\tblam")
              '  foo\n    bar blam'
          """
          if '\t' not in text:
              return text
          return self._detab_re.subn(self._detab_sub, text)[0]
  
      # I broke out the html5 tags here and add them to _block_tags_a and
      # _block_tags_b.  This way html5 tags are easy to keep track of.
      _html5tags = '|article|aside|header|hgroup|footer|nav|section|figure|figcaption'
  
      _block_tags_a = 'p|div|h[1-6]|blockquote|pre|table|dl|ol|ul|script|noscript|form|fieldset|iframe|math|ins|del'
      _block_tags_a += _html5tags
  
      _strict_tag_block_re = re.compile(r"""
          (                       # save in \1
              ^                   # start of line  (with re.M)
              <(%s)               # start tag = \2
              \b                  # word break
              (.*\n)*?            # any number of lines, minimally matching
              </\2>               # the matching end tag
              [ \t]*              # trailing spaces/tabs
              (?=\n+|\Z)          # followed by a newline or end of document
          )
          """ % _block_tags_a,
          re.X | re.M)
  
      _block_tags_b = 'p|div|h[1-6]|blockquote|pre|table|dl|ol|ul|script|noscript|form|fieldset|iframe|math'
      _block_tags_b += _html5tags
  
      _liberal_tag_block_re = re.compile(r"""
          (                       # save in \1
              ^                   # start of line  (with re.M)
              <(%s)               # start tag = \2
              \b                  # word break
              (.*\n)*?            # any number of lines, minimally matching
              .*</\2>             # the matching end tag
              [ \t]*              # trailing spaces/tabs
              (?=\n+|\Z)          # followed by a newline or end of document
          )
          """ % _block_tags_b,
          re.X | re.M)
  
      _html_markdown_attr_re = re.compile(
          r'''\s+markdown=("1"|'1')''')
      def _hash_html_block_sub(self, match, raw=False):
          html = match.group(1)
          if raw and self.safe_mode:
              html = self._sanitize_html(html)
          elif 'markdown-in-html' in self.extras and 'markdown=' in html:
              first_line = html.split('\n', 1)[0]
              m = self._html_markdown_attr_re.search(first_line)
              if m:
                  lines = html.split('\n')
                  middle = '\n'.join(lines[1:-1])
                  last_line = lines[-1]
                  first_line = first_line[:m.start()] + first_line[m.end():]
                  f_key = _hash_text(first_line)
                  self.html_blocks[f_key] = first_line
                  l_key = _hash_text(last_line)
                  self.html_blocks[l_key] = last_line
                  return ''.join(["\n\n", f_key,
                      "\n\n", middle, "\n\n",
                      l_key, "\n\n"])
          key = _hash_text(html)
          self.html_blocks[key] = html
          return "\n\n" + key + "\n\n"
  
      def _hash_html_blocks(self, text, raw=False):
          """Hashify HTML blocks
  
          We only want to do this for block-level HTML tags, such as headers,
          lists, and tables. That's because we still want to wrap <p>s around
          "paragraphs" that are wrapped in non-block-level tags, such as anchors,
          phrase emphasis, and spans. The list of tags we're looking for is
          hard-coded.
  
          @param raw {boolean} indicates if these are raw HTML blocks in
              the original source. It makes a difference in "safe" mode.
          """
          if '<' not in text:
              return text
  
          # Pass `raw` value into our calls to self._hash_html_block_sub.
          hash_html_block_sub = _curry(self._hash_html_block_sub, raw=raw)
  
          # First, look for nested blocks, e.g.:
          #   <div>
          #       <div>
          #       tags for inner block must be indented.
          #       </div>
          #   </div>
          #
          # The outermost tags must start at the left margin for this to match, and
          # the inner nested divs must be indented.
          # We need to do this before the next, more liberal match, because the next
          # match will start at the first `<div>` and stop at the first `</div>`.
          text = self._strict_tag_block_re.sub(hash_html_block_sub, text)
  
          # Now match more liberally, simply from `\n<tag>` to `</tag>\n`
          text = self._liberal_tag_block_re.sub(hash_html_block_sub, text)
  
          # Special case just for <hr />. It was easier to make a special
          # case than to make the other regex more complicated.
          if "<hr" in text:
              _hr_tag_re = _hr_tag_re_from_tab_width(self.tab_width)
              text = _hr_tag_re.sub(hash_html_block_sub, text)
  
          # Special case for standalone HTML comments:
          if "<!--" in text:
              start = 0
              while True:
                  # Delimiters for next comment block.
                  try:
                      start_idx = text.index("<!--", start)
                  except ValueError:
                      break
                  try:
                      end_idx = text.index("-->", start_idx) + 3
                  except ValueError:
                      break
  
                  # Start position for next comment block search.
                  start = end_idx
  
                  # Validate whitespace before comment.
                  if start_idx:
                      # - Up to `tab_width - 1` spaces before start_idx.
                      for i in range(self.tab_width - 1):
                          if text[start_idx - 1] != ' ':
                              break
                          start_idx -= 1
                          if start_idx == 0:
                              break
                      # - Must be preceded by 2 newlines or hit the start of
                      #   the document.
                      if start_idx == 0:
                          pass
                      elif start_idx == 1 and text[0] == '\n':
                          start_idx = 0  # to match minute detail of Markdown.pl regex
                      elif text[start_idx-2:start_idx] == '\n\n':
                          pass
                      else:
                          break
  
                  # Validate whitespace after comment.
                  # - Any number of spaces and tabs.
                  while end_idx < len(text):
                      if text[end_idx] not in ' \t':
                          break
                      end_idx += 1
                  # - Must be following by 2 newlines or hit end of text.
                  if text[end_idx:end_idx+2] not in ('', '\n', '\n\n'):
                      continue
  
                  # Escape and hash (must match `_hash_html_block_sub`).
                  html = text[start_idx:end_idx]
                  if raw and self.safe_mode:
                      html = self._sanitize_html(html)
                  key = _hash_text(html)
                  self.html_blocks[key] = html
                  text = text[:start_idx] + "\n\n" + key + "\n\n" + text[end_idx:]
  
          if "xml" in self.extras:
              # Treat XML processing instructions and namespaced one-liner
              # tags as if they were block HTML tags. E.g., if standalone
              # (i.e. are their own paragraph), the following do not get
              # wrapped in a <p> tag:
              #    <?foo bar?>
              #
              #    <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="chapter_1.md"/>
              _xml_oneliner_re = _xml_oneliner_re_from_tab_width(self.tab_width)
              text = _xml_oneliner_re.sub(hash_html_block_sub, text)
  
          return text
  
      def _strip_link_definitions(self, text):
          # Strips link definitions from text, stores the URLs and titles in
          # hash references.
          less_than_tab = self.tab_width - 1
  
          # Link defs are in the form:
          #   [id]: url "optional title"
          _link_def_re = re.compile(r"""
              ^[ ]{0,%d}\[(.+)\]: # id = \1
                [ \t]*
                \n?               # maybe *one* newline
                [ \t]*
              <?(.+?)>?           # url = \2
                [ \t]*
              (?:
                  \n?             # maybe one newline
                  [ \t]*
                  (?<=\s)         # lookbehind for whitespace
                  ['"(]
                  ([^\n]*)        # title = \3
                  ['")]
                  [ \t]*
              )?  # title is optional
              (?:\n+|\Z)
              """ % less_than_tab, re.X | re.M | re.U)
          return _link_def_re.sub(self._extract_link_def_sub, text)
  
      def _extract_link_def_sub(self, match):
          id, url, title = match.groups()
          key = id.lower()    # Link IDs are case-insensitive
          self.urls[key] = self._encode_amps_and_angles(url)
          if title:
              self.titles[key] = title
          return ""
  
      def _extract_footnote_def_sub(self, match):
          id, text = match.groups()
          text = _dedent(text, skip_first_line=not text.startswith('\n')).strip()
          normed_id = re.sub(r'\W', '-', id)
          # Ensure footnote text ends with a couple newlines (for some
          # block gamut matches).
          self.footnotes[normed_id] = text + "\n\n"
          return ""
  
      def _strip_footnote_definitions(self, text):
          """A footnote definition looks like this:
  
              [^note-id]: Text of the note.
  
                  May include one or more indented paragraphs.
  
          Where,
          - The 'note-id' can be pretty much anything, though typically it
            is the number of the footnote.
          - The first paragraph may start on the next line, like so:
  
              [^note-id]:
                  Text of the note.
          """
          less_than_tab = self.tab_width - 1
          footnote_def_re = re.compile(r'''
              ^[ ]{0,%d}\[\^(.+)\]:   # id = \1
              [ \t]*
              (                       # footnote text = \2
                # First line need not start with the spaces.
                (?:\s*.*\n+)
                (?:
                  (?:[ ]{%d} | \t)  # Subsequent lines must be indented.
                  .*\n+
                )*
              )
              # Lookahead for non-space at line-start, or end of doc.
              (?:(?=^[ ]{0,%d}\S)|\Z)
              ''' % (less_than_tab, self.tab_width, self.tab_width),
              re.X | re.M)
          return footnote_def_re.sub(self._extract_footnote_def_sub, text)
  
  
      _hr_data = [
          ('*', re.compile(r"^[ ]{0,3}\*(.*?)$", re.M)),
          ('-', re.compile(r"^[ ]{0,3}\-(.*?)$", re.M)),
          ('_', re.compile(r"^[ ]{0,3}\_(.*?)$", re.M)),
      ]
  
      def _run_block_gamut(self, text):
          # These are all the transformations that form block-level
          # tags like paragraphs, headers, and list items.
  
          if "fenced-code-blocks" in self.extras:
              text = self._do_fenced_code_blocks(text)
  
          text = self._do_headers(text)
  
          # Do Horizontal Rules:
          # On the number of spaces in horizontal rules: The spec is fuzzy: "If
          # you wish, you may use spaces between the hyphens or asterisks."
          # Markdown.pl 1.0.1's hr regexes limit the number of spaces between the
          # hr chars to one or two. We'll reproduce that limit here.
          hr = "\n<hr"+self.empty_element_suffix+"\n"
          for ch, regex in self._hr_data:
              if ch in text:
                  for m in reversed(list(regex.finditer(text))):
                      tail = m.group(1).rstrip()
                      if not tail.strip(ch + ' ') and tail.count("   ") == 0:
                          start, end = m.span()
                          text = text[:start] + hr + text[end:]
  
          text = self._do_lists(text)
  
          if "pyshell" in self.extras:
              text = self._prepare_pyshell_blocks(text)
          if "wiki-tables" in self.extras:
              text = self._do_wiki_tables(text)
  
          text = self._do_code_blocks(text)
  
          text = self._do_block_quotes(text)
  
          # We already ran _HashHTMLBlocks() before, in Markdown(), but that
          # was to escape raw HTML in the original Markdown source. This time,
          # we're escaping the markup we've just created, so that we don't wrap
          # <p> tags around block-level tags.
          text = self._hash_html_blocks(text)
  
          text = self._form_paragraphs(text)
  
          return text
  
      def _pyshell_block_sub(self, match):
          lines = match.group(0).splitlines(0)
          _dedentlines(lines)
          indent = ' ' * self.tab_width
          s = ('\n' # separate from possible cuddled paragraph
               + indent + ('\n'+indent).join(lines)
               + '\n\n')
          return s
  
      def _prepare_pyshell_blocks(self, text):
          """Ensure that Python interactive shell sessions are put in
          code blocks -- even if not properly indented.
          """
          if ">>>" not in text:
              return text
  
          less_than_tab = self.tab_width - 1
          _pyshell_block_re = re.compile(r"""
              ^([ ]{0,%d})>>>[ ].*\n   # first line
              ^(\1.*\S+.*\n)*         # any number of subsequent lines
              ^\n                     # ends with a blank line
              """ % less_than_tab, re.M | re.X)
  
          return _pyshell_block_re.sub(self._pyshell_block_sub, text)
  
      def _wiki_table_sub(self, match):
          ttext = match.group(0).strip()
          #print 'wiki table: %r' % match.group(0)
          rows = []
          for line in ttext.splitlines(0):
              line = line.strip()[2:-2].strip()
              row = [c.strip() for c in re.split(r'(?<!\\)\|\|', line)]
              rows.append(row)
          #pprint(rows)
          hlines = ['<table>', '<tbody>']
          for row in rows:
              hrow = ['<tr>']
              for cell in row:
                  hrow.append('<td>')
                  hrow.append(self._run_span_gamut(cell))
                  hrow.append('</td>')
              hrow.append('</tr>')
              hlines.append(''.join(hrow))
          hlines += ['</tbody>', '</table>']
          return '\n'.join(hlines) + '\n'
  
      def _do_wiki_tables(self, text):
          # Optimization.
          if "||" not in text:
              return text
  
          less_than_tab = self.tab_width - 1
          wiki_table_re = re.compile(r'''
              (?:(?<=\n\n)|\A\n?)            # leading blank line
              ^([ ]{0,%d})\|\|.+?\|\|[ ]*\n  # first line
              (^\1\|\|.+?\|\|\n)*        # any number of subsequent lines
              ''' % less_than_tab, re.M | re.X)
          return wiki_table_re.sub(self._wiki_table_sub, text)
  
      def _run_span_gamut(self, text):
          # These are all the transformations that occur *within* block-level
          # tags like paragraphs, headers, and list items.
  
          text = self._do_code_spans(text)
  
          text = self._escape_special_chars(text)
  
          # Process anchor and image tags.
          text = self._do_links(text)
  
          # Make links out of things like `<http://example.com/>`
          # Must come after _do_links(), because you can use < and >
          # delimiters in inline links like [this](<url>).
          text = self._do_auto_links(text)
  
          if "link-patterns" in self.extras:
              text = self._do_link_patterns(text)
  
          text = self._encode_amps_and_angles(text)
  
          text = self._do_italics_and_bold(text)
  
          if "smarty-pants" in self.extras:
              text = self._do_smart_punctuation(text)
  
          # Do hard breaks:
          text = re.sub(r" {2,}\n", " <br%s\n" % self.empty_element_suffix, text)
  
          return text
  
      # "Sorta" because auto-links are identified as "tag" tokens.
      _sorta_html_tokenize_re = re.compile(r"""
          (
              # tag
              </?
              (?:\w+)                                     # tag name
              (?:\s+(?:[\w-]+:)?[\w-]+=(?:".*?"|'.*?'))*  # attributes
              \s*/?>
              |
              # auto-link (e.g., <http://www.activestate.com/>)
              <\w+[^>]*>
              |
              <!--.*?-->      # comment
              |
              <\?.*?\?>       # processing instruction
          )
          """, re.X)
  
      def _escape_special_chars(self, text):
          # Python markdown note: the HTML tokenization here differs from
          # that in Markdown.pl, hence the behaviour for subtle cases can
          # differ (I believe the tokenizer here does a better job because
          # it isn't susceptible to unmatched '<' and '>' in HTML tags).
          # Note, however, that '>' is not allowed in an auto-link URL
          # here.
          escaped = []
          is_html_markup = False
          for token in self._sorta_html_tokenize_re.split(text):
              if is_html_markup:
                  # Within tags/HTML-comments/auto-links, encode * and _
                  # so they don't conflict with their use in Markdown for
                  # italics and strong.  We're replacing each such
                  # character with its corresponding MD5 checksum value;
                  # this is likely overkill, but it should prevent us from
                  # colliding with the escape values by accident.
                  escaped.append(token.replace('*', self._escape_table['*'])
                                      .replace('_', self._escape_table['_']))
              else:
                  escaped.append(self._encode_backslash_escapes(token))
              is_html_markup = not is_html_markup
          return ''.join(escaped)
  
      def _hash_html_spans(self, text):
          # Used for safe_mode.
  
          def _is_auto_link(s):
              if ':' in s and self._auto_link_re.match(s):
                  return True
              elif '@' in s and self._auto_email_link_re.match(s):
                  return True
              return False
  
          tokens = []
          is_html_markup = False
          for token in self._sorta_html_tokenize_re.split(text):
              if is_html_markup and not _is_auto_link(token):
                  sanitized = self._sanitize_html(token)
                  key = _hash_text(sanitized)
                  self.html_spans[key] = sanitized
                  tokens.append(key)
              else:
                  tokens.append(token)
              is_html_markup = not is_html_markup
          return ''.join(tokens)
  
      def _unhash_html_spans(self, text):
          for key, sanitized in list(self.html_spans.items()):
              text = text.replace(key, sanitized)
          return text
  
      def _sanitize_html(self, s):
          if self.safe_mode == "replace":
              return self.html_removed_text
          elif self.safe_mode == "escape":
              replacements = [
                  ('&', '&amp;'),
                  ('<', '&lt;'),
                  ('>', '&gt;'),
              ]
              for before, after in replacements:
                  s = s.replace(before, after)
              return s
          else:
              raise MarkdownError("invalid value for 'safe_mode': %r (must be "
                                  "'escape' or 'replace')" % self.safe_mode)
  
      _tail_of_inline_link_re = re.compile(r'''
            # Match tail of: [text](/url/) or [text](/url/ "title")
            \(            # literal paren
              [ \t]*
              (?P<url>            # \1
                  <.*?>
                  |
                  .*?
              )
              [ \t]*
              (                   # \2
                (['"])            # quote char = \3
                (?P<title>.*?)
                \3                # matching quote
              )?                  # title is optional
            \)
          ''', re.X | re.S)
      _tail_of_reference_link_re = re.compile(r'''
            # Match tail of: [text][id]
            [ ]?          # one optional space
            (?:\n[ ]*)?   # one optional newline followed by spaces
            \[
              (?P<id>.*?)
            \]
          ''', re.X | re.S)
  
      def _do_links(self, text):
          """Turn Markdown link shortcuts into XHTML <a> and <img> tags.
  
          This is a combination of Markdown.pl's _DoAnchors() and
          _DoImages(). They are done together because that simplified the
          approach. It was necessary to use a different approach than
          Markdown.pl because of the lack of atomic matching support in
          Python's regex engine used in $g_nested_brackets.
          """
          MAX_LINK_TEXT_SENTINEL = 3000  # markdown2 issue 24
  
          # `anchor_allowed_pos` is used to support img links inside
          # anchors, but not anchors inside anchors. An anchor's start
          # pos must be `>= anchor_allowed_pos`.
          anchor_allowed_pos = 0
  
          curr_pos = 0
          while True: # Handle the next link.
              # The next '[' is the start of:
              # - an inline anchor:   [text](url "title")
              # - a reference anchor: [text][id]
              # - an inline img:      ![text](url "title")
              # - a reference img:    ![text][id]
              # - a footnote ref:     [^id]
              #   (Only if 'footnotes' extra enabled)
              # - a footnote defn:    [^id]: ...
              #   (Only if 'footnotes' extra enabled) These have already
              #   been stripped in _strip_footnote_definitions() so no
              #   need to watch for them.
              # - a link definition:  [id]: url "title"
              #   These have already been stripped in
              #   _strip_link_definitions() so no need to watch for them.
              # - not markup:         [...anything else...
              try:
                  start_idx = text.index('[', curr_pos)
              except ValueError:
                  break
              text_length = len(text)
  
              # Find the matching closing ']'.
              # Markdown.pl allows *matching* brackets in link text so we
              # will here too. Markdown.pl *doesn't* currently allow
              # matching brackets in img alt text -- we'll differ in that
              # regard.
              bracket_depth = 0
              for p in range(start_idx+1, min(start_idx+MAX_LINK_TEXT_SENTINEL,
                                              text_length)):
                  ch = text[p]
                  if ch == ']':
                      bracket_depth -= 1
                      if bracket_depth < 0:
                          break
                  elif ch == '[':
                      bracket_depth += 1
              else:
                  # Closing bracket not found within sentinel length.
                  # This isn't markup.
                  curr_pos = start_idx + 1
                  continue
              link_text = text[start_idx+1:p]
  
              # Possibly a footnote ref?
              if "footnotes" in self.extras and link_text.startswith("^"):
                  normed_id = re.sub(r'\W', '-', link_text[1:])
                  if normed_id in self.footnotes:
                      self.footnote_ids.append(normed_id)
                      result = '<sup class="footnote-ref" id="fnref-%s">' \
                               '<a href="#fn-%s">%s</a></sup>' \
                               % (normed_id, normed_id, len(self.footnote_ids))
                      text = text[:start_idx] + result + text[p+1:]
                  else:
                      # This id isn't defined, leave the markup alone.
                      curr_pos = p+1
                  continue
  
              # Now determine what this is by the remainder.
              p += 1
              if p == text_length:
                  return text
  
              # Inline anchor or img?
              if text[p] == '(': # attempt at perf improvement
                  match = self._tail_of_inline_link_re.match(text, p)
                  if match:
                      # Handle an inline anchor or img.
                      is_img = start_idx > 0 and text[start_idx-1] == "!"
                      if is_img:
                          start_idx -= 1
  
                      url, title = match.group("url"), match.group("title")
                      if url and url[0] == '<':
                          url = url[1:-1]  # '<url>' -> 'url'
                      # We've got to encode these to avoid conflicting
                      # with italics/bold.
                      url = url.replace('*', self._escape_table['*']) \
                               .replace('_', self._escape_table['_'])
                      if title:
                          title_str = ' title="%s"' % (
                              _xml_escape_attr(title)
                                  .replace('*', self._escape_table['*'])
                                  .replace('_', self._escape_table['_']))
                      else:
                          title_str = ''
                      if is_img:
                          result = '<img src="%s" alt="%s"%s%s' \
                              % (url.replace('"', '&quot;'),
                                 _xml_escape_attr(link_text),
                                 title_str, self.empty_element_suffix)
                          if "smarty-pants" in self.extras:
                              result = result.replace('"', self._escape_table['"'])
                          curr_pos = start_idx + len(result)
                          text = text[:start_idx] + result + text[match.end():]
                      elif start_idx >= anchor_allowed_pos:
                          result_head = '<a href="%s"%s>' % (url, title_str)
                          result = '%s%s</a>' % (result_head, link_text)
                          if "smarty-pants" in self.extras:
                              result = result.replace('"', self._escape_table['"'])
                          # <img> allowed from curr_pos on, <a> from
                          # anchor_allowed_pos on.
                          curr_pos = start_idx + len(result_head)
                          anchor_allowed_pos = start_idx + len(result)
                          text = text[:start_idx] + result + text[match.end():]
                      else:
                          # Anchor not allowed here.
                          curr_pos = start_idx + 1
                      continue
  
              # Reference anchor or img?
              else:
                  match = self._tail_of_reference_link_re.match(text, p)
                  if match:
                      # Handle a reference-style anchor or img.
                      is_img = start_idx > 0 and text[start_idx-1] == "!"
                      if is_img:
                          start_idx -= 1
                      link_id = match.group("id").lower()
                      if not link_id:
                          link_id = link_text.lower()  # for links like [this][]
                      if link_id in self.urls:
                          url = self.urls[link_id]
                          # We've got to encode these to avoid conflicting
                          # with italics/bold.
                          url = url.replace('*', self._escape_table['*']) \
                                   .replace('_', self._escape_table['_'])
                          title = self.titles.get(link_id)
                          if title:
                              before = title
                              title = _xml_escape_attr(title) \
                                  .replace('*', self._escape_table['*']) \
                                  .replace('_', self._escape_table['_'])
                              title_str = ' title="%s"' % title
                          else:
                              title_str = ''
                          if is_img:
                              result = '<img src="%s" alt="%s"%s%s' \
                                  % (url.replace('"', '&quot;'),
                                     link_text.replace('"', '&quot;'),
                                     title_str, self.empty_element_suffix)
                              if "smarty-pants" in self.extras:
                                  result = result.replace('"', self._escape_table['"'])
                              curr_pos = start_idx + len(result)
                              text = text[:start_idx] + result + text[match.end():]
                          elif start_idx >= anchor_allowed_pos:
                              result = '<a href="%s"%s>%s</a>' \
                                  % (url, title_str, link_text)
                              result_head = '<a href="%s"%s>' % (url, title_str)
                              result = '%s%s</a>' % (result_head, link_text)
                              if "smarty-pants" in self.extras:
                                  result = result.replace('"', self._escape_table['"'])
                              # <img> allowed from curr_pos on, <a> from
                              # anchor_allowed_pos on.
                              curr_pos = start_idx + len(result_head)
                              anchor_allowed_pos = start_idx + len(result)
                              text = text[:start_idx] + result + text[match.end():]
                          else:
                              # Anchor not allowed here.
                              curr_pos = start_idx + 1
                      else:
                          # This id isn't defined, leave the markup alone.
                          curr_pos = match.end()
                      continue
  
              # Otherwise, it isn't markup.
              curr_pos = start_idx + 1
  
          return text
  
      def header_id_from_text(self, text, prefix, n):
          """Generate a header id attribute value from the given header
          HTML content.
  
          This is only called if the "header-ids" extra is enabled.
          Subclasses may override this for different header ids.
  
          @param text {str} The text of the header tag
          @param prefix {str} The requested prefix for header ids. This is the
              value of the "header-ids" extra key, if any. Otherwise, None.
          @param n {int} The <hN> tag number, i.e. `1` for an <h1> tag.
          @returns {str} The value for the header tag's "id" attribute. Return
              None to not have an id attribute and to exclude this header from
              the TOC (if the "toc" extra is specified).
          """
          header_id = _slugify(text)
          if prefix and isinstance(prefix, base_string_type):
              header_id = prefix + '-' + header_id
          if header_id in self._count_from_header_id:
              self._count_from_header_id[header_id] += 1
              header_id += '-%s' % self._count_from_header_id[header_id]
          else:
              self._count_from_header_id[header_id] = 1
          return header_id
  
      _toc = None
      def _toc_add_entry(self, level, id, name):
          if self._toc is None:
              self._toc = []
          self._toc.append((level, id, self._unescape_special_chars(name)))
  
      _setext_h_re = re.compile(r'^(.+)[ \t]*\n(=+|-+)[ \t]*\n+', re.M)
      def _setext_h_sub(self, match):
          n = {"=": 1, "-": 2}[match.group(2)[0]]
          demote_headers = self.extras.get("demote-headers")
          if demote_headers:
              n = min(n + demote_headers, 6)
          header_id_attr = ""
          if "header-ids" in self.extras:
              header_id = self.header_id_from_text(match.group(1),
                  self.extras["header-ids"], n)
              if header_id:
                  header_id_attr = ' id="%s"' % header_id
          html = self._run_span_gamut(match.group(1))
          if "toc" in self.extras and header_id:
              self._toc_add_entry(n, header_id, html)
          return "<h%d%s>%s</h%d>\n\n" % (n, header_id_attr, html, n)
  
      _atx_h_re = re.compile(r'''
          ^(\#{1,6})  # \1 = string of #'s
          [ \t]+
          (.+?)       # \2 = Header text
          [ \t]*
          (?<!\\)     # ensure not an escaped trailing '#'
          \#*         # optional closing #'s (not counted)
          \n+
          ''', re.X | re.M)
      def _atx_h_sub(self, match):
          n = len(match.group(1))
          demote_headers = self.extras.get("demote-headers")
          if demote_headers:
              n = min(n + demote_headers, 6)
          header_id_attr = ""
          if "header-ids" in self.extras:
              header_id = self.header_id_from_text(match.group(2),
                  self.extras["header-ids"], n)
              if header_id:
                  header_id_attr = ' id="%s"' % header_id
          html = self._run_span_gamut(match.group(2))
          if "toc" in self.extras and header_id:
              self._toc_add_entry(n, header_id, html)
          return "<h%d%s>%s</h%d>\n\n" % (n, header_id_attr, html, n)
  
      def _do_headers(self, text):
          # Setext-style headers:
          #     Header 1
          #     ========
          #
          #     Header 2
          #     --------
          text = self._setext_h_re.sub(self._setext_h_sub, text)
  
          # atx-style headers:
          #   # Header 1
          #   ## Header 2
          #   ## Header 2 with closing hashes ##
          #   ...
          #   ###### Header 6
          text = self._atx_h_re.sub(self._atx_h_sub, text)
  
          return text
  
  
      _marker_ul_chars  = '*+-'
      _marker_any = r'(?:[%s]|\d+\.)' % _marker_ul_chars
      _marker_ul = '(?:[%s])' % _marker_ul_chars
      _marker_ol = r'(?:\d+\.)'
  
      def _list_sub(self, match):
          lst = match.group(1)
          lst_type = match.group(3) in self._marker_ul_chars and "ul" or "ol"
          result = self._process_list_items(lst)
          if self.list_level:
              return "<%s>\n%s</%s>\n" % (lst_type, result, lst_type)
          else:
              return "<%s>\n%s</%s>\n\n" % (lst_type, result, lst_type)
  
      def _do_lists(self, text):
          # Form HTML ordered (numbered) and unordered (bulleted) lists.
  
          # Iterate over each *non-overlapping* list match.
          pos = 0
          while True:
              # Find the *first* hit for either list style (ul or ol). We
              # match ul and ol separately to avoid adjacent lists of different
              # types running into each other (see issue #16).
              hits = []
              for marker_pat in (self._marker_ul, self._marker_ol):
                  less_than_tab = self.tab_width - 1
                  whole_list = r'''
                      (                   # \1 = whole list
                        (                 # \2
                          [ ]{0,%d}
                          (%s)            # \3 = first list item marker
                          [ \t]+
                          (?!\ *\3\ )     # '- - - ...' isn't a list. See 'not_quite_a_list' test case.
                        )
                        (?:.+?)
                        (                 # \4
                            \Z
                          |
                            \n{2,}
                            (?=\S)
                            (?!           # Negative lookahead for another list item marker
                              [ \t]*
                              %s[ \t]+
                            )
                        )
                      )
                  ''' % (less_than_tab, marker_pat, marker_pat)
                  if self.list_level:  # sub-list
                      list_re = re.compile("^"+whole_list, re.X | re.M | re.S)
                  else:
                      list_re = re.compile(r"(?:(?<=\n\n)|\A\n?)"+whole_list,
                                           re.X | re.M | re.S)
                  match = list_re.search(text, pos)
                  if match:
                      hits.append((match.start(), match))
              if not hits:
                  break
              hits.sort()
              match = hits[0][1]
              start, end = match.span()
              text = text[:start] + self._list_sub(match) + text[end:]
              pos = end
  
          return text
  
      _list_item_re = re.compile(r'''
          (\n)?                   # leading line = \1
          (^[ \t]*)               # leading whitespace = \2
          (?P<marker>%s) [ \t]+   # list marker = \3
          ((?:.+?)                # list item text = \4
           (\n{1,2}))             # eols = \5
          (?= \n* (\Z | \2 (?P<next_marker>%s) [ \t]+))
          ''' % (_marker_any, _marker_any),
          re.M | re.X | re.S)
  
      _last_li_endswith_two_eols = False
      def _list_item_sub(self, match):
          item = match.group(4)
          leading_line = match.group(1)
          leading_space = match.group(2)
          if leading_line or "\n\n" in item or self._last_li_endswith_two_eols:
              item = self._run_block_gamut(self._outdent(item))
          else:
              # Recursion for sub-lists:
              item = self._do_lists(self._outdent(item))
              if item.endswith('\n'):
                  item = item[:-1]
              item = self._run_span_gamut(item)
          self._last_li_endswith_two_eols = (len(match.group(5)) == 2)
          return "<li>%s</li>\n" % item
  
      def _process_list_items(self, list_str):
          # Process the contents of a single ordered or unordered list,
          # splitting it into individual list items.
  
          # The $g_list_level global keeps track of when we're inside a list.
          # Each time we enter a list, we increment it; when we leave a list,
          # we decrement. If it's zero, we're not in a list anymore.
          #
          # We do this because when we're not inside a list, we want to treat
          # something like this:
          #
          #       I recommend upgrading to version
          #       8. Oops, now this line is treated
          #       as a sub-list.
          #
          # As a single paragraph, despite the fact that the second line starts
          # with a digit-period-space sequence.
          #
          # Whereas when we're inside a list (or sub-list), that line will be
          # treated as the start of a sub-list. What a kludge, huh? This is
          # an aspect of Markdown's syntax that's hard to parse perfectly
          # without resorting to mind-reading. Perhaps the solution is to
          # change the syntax rules such that sub-lists must start with a
          # starting cardinal number; e.g. "1." or "a.".
          self.list_level += 1
          self._last_li_endswith_two_eols = False
          list_str = list_str.rstrip('\n') + '\n'
          list_str = self._list_item_re.sub(self._list_item_sub, list_str)
          self.list_level -= 1
          return list_str
  
      def _get_pygments_lexer(self, lexer_name):
          try:
              from pygments import lexers, util
          except ImportError:
              return None
          try:
              return lexers.get_lexer_by_name(lexer_name)
          except util.ClassNotFound:
              return None
  
      def _color_with_pygments(self, codeblock, lexer, **formatter_opts):
          import pygments
          import pygments.formatters
  
          class HtmlCodeFormatter(pygments.formatters.HtmlFormatter):
              def _wrap_code(self, inner):
                  """A function for use in a Pygments Formatter which
                  wraps in <code> tags.
                  """
                  yield 0, "<code>"
                  for tup in inner:
                      yield tup
                  yield 0, "</code>"
  
              def wrap(self, source, outfile):
                  """Return the source with a code, pre, and div."""
                  return self._wrap_div(self._wrap_pre(self._wrap_code(source)))
  
          formatter_opts.setdefault("cssclass", "codehilite")
          formatter = HtmlCodeFormatter(**formatter_opts)
          return pygments.highlight(codeblock, lexer, formatter)
  
      def _code_block_sub(self, match, is_fenced_code_block=False):
          lexer_name = None
          if is_fenced_code_block:
              lexer_name = match.group(1)
              if lexer_name:
                  formatter_opts = self.extras['fenced-code-blocks'] or {}
              codeblock = match.group(2)
              codeblock = codeblock[:-1]  # drop one trailing newline
          else:
              codeblock = match.group(1)
              codeblock = self._outdent(codeblock)
              codeblock = self._detab(codeblock)
              codeblock = codeblock.lstrip('\n')  # trim leading newlines
              codeblock = codeblock.rstrip()      # trim trailing whitespace
  
              # Note: "code-color" extra is DEPRECATED.
              if "code-color" in self.extras and codeblock.startswith(":::"):
                  lexer_name, rest = codeblock.split('\n', 1)
                  lexer_name = lexer_name[3:].strip()
                  codeblock = rest.lstrip("\n")   # Remove lexer declaration line.
                  formatter_opts = self.extras['code-color'] or {}
  
          if lexer_name:
              lexer = self._get_pygments_lexer(lexer_name)
              if lexer:
                  colored = self._color_with_pygments(codeblock, lexer,
                                                      **formatter_opts)
                  return "\n\n%s\n\n" % colored
  
          codeblock = self._encode_code(codeblock)
          pre_class_str = self._html_class_str_from_tag("pre")
          code_class_str = self._html_class_str_from_tag("code")
          return "\n\n<pre%s><code%s>%s\n</code></pre>\n\n" % (
              pre_class_str, code_class_str, codeblock)
  
      def _html_class_str_from_tag(self, tag):
          """Get the appropriate ' class="..."' string (note the leading
          space), if any, for the given tag.
          """
          if "html-classes" not in self.extras:
              return ""
          try:
              html_classes_from_tag = self.extras["html-classes"]
          except TypeError:
              return ""
          else:
              if tag in html_classes_from_tag:
                  return ' class="%s"' % html_classes_from_tag[tag]
          return ""
  
      def _do_code_blocks(self, text):
          """Process Markdown `<pre><code>` blocks."""
          code_block_re = re.compile(r'''
              (?:\n\n|\A\n?)
              (               # $1 = the code block -- one or more lines, starting with a space/tab
                (?:
                  (?:[ ]{%d} | \t)  # Lines must start with a tab or a tab-width of spaces
                  .*\n+
                )+
              )
              ((?=^[ ]{0,%d}\S)|\Z)   # Lookahead for non-space at line-start, or end of doc
              ''' % (self.tab_width, self.tab_width),
              re.M | re.X)
          return code_block_re.sub(self._code_block_sub, text)
  
      _fenced_code_block_re = re.compile(r'''
          (?:\n\n|\A\n?)
          ^```([\w+-]+)?[ \t]*\n      # opening fence, $1 = optional lang
          (.*?)                       # $2 = code block content
          ^```[ \t]*\n                # closing fence
          ''', re.M | re.X | re.S)
  
      def _fenced_code_block_sub(self, match):
          return self._code_block_sub(match, is_fenced_code_block=True);
  
      def _do_fenced_code_blocks(self, text):
          """Process ```-fenced unindented code blocks ('fenced-code-blocks' extra)."""
          return self._fenced_code_block_re.sub(self._fenced_code_block_sub, text)
  
      # Rules for a code span:
      # - backslash escapes are not interpreted in a code span
      # - to include one or or a run of more backticks the delimiters must
      #   be a longer run of backticks
      # - cannot start or end a code span with a backtick; pad with a
      #   space and that space will be removed in the emitted HTML
      # See `test/tm-cases/escapes.text` for a number of edge-case
      # examples.
      _code_span_re = re.compile(r'''
              (?<!\\)
              (`+)        # \1 = Opening run of `
              (?!`)       # See Note A test/tm-cases/escapes.text
              (.+?)       # \2 = The code block
              (?<!`)
              \1          # Matching closer
              (?!`)
          ''', re.X | re.S)
  
      def _code_span_sub(self, match):
          c = match.group(2).strip(" \t")
          c = self._encode_code(c)
          return "<code>%s</code>" % c
  
      def _do_code_spans(self, text):
          #   *   Backtick quotes are used for <code></code> spans.
          #
          #   *   You can use multiple backticks as the delimiters if you want to
          #       include literal backticks in the code span. So, this input:
          #
          #         Just type ``foo `bar` baz`` at the prompt.
          #
          #       Will translate to:
          #
          #         <p>Just type <code>foo `bar` baz</code> at the prompt.</p>
          #
          #       There's no arbitrary limit to the number of backticks you
          #       can use as delimters. If you need three consecutive backticks
          #       in your code, use four for delimiters, etc.
          #
          #   *   You can use spaces to get literal backticks at the edges:
          #
          #         ... type `` `bar` `` ...
          #
          #       Turns to:
          #
          #         ... type <code>`bar`</code> ...
          return self._code_span_re.sub(self._code_span_sub, text)
  
      def _encode_code(self, text):
          """Encode/escape certain characters inside Markdown code runs.
          The point is that in code, these characters are literals,
          and lose their special Markdown meanings.
          """
          replacements = [
              # Encode all ampersands; HTML entities are not
              # entities within a Markdown code span.
              ('&', '&amp;'),
              # Do the angle bracket song and dance:
              ('<', '&lt;'),
              ('>', '&gt;'),
          ]
          for before, after in replacements:
              text = text.replace(before, after)
          hashed = _hash_text(text)
          self._escape_table[text] = hashed
          return hashed
  
      _strong_re = re.compile(r"(\*\*|__)(?=\S)(.+?[*_]*)(?<=\S)\1", re.S)
      _em_re = re.compile(r"(\*|_)(?=\S)(.+?)(?<=\S)\1", re.S)
      _code_friendly_strong_re = re.compile(r"\*\*(?=\S)(.+?[*_]*)(?<=\S)\*\*", re.S)
      _code_friendly_em_re = re.compile(r"\*(?=\S)(.+?)(?<=\S)\*", re.S)
      def _do_italics_and_bold(self, text):
          # <strong> must go first:
          if "code-friendly" in self.extras:
              text = self._code_friendly_strong_re.sub(r"<strong>\1</strong>", text)
              text = self._code_friendly_em_re.sub(r"<em>\1</em>", text)
          else:
              text = self._strong_re.sub(r"<strong>\2</strong>", text)
              text = self._em_re.sub(r"<em>\2</em>", text)
          return text
  
      # "smarty-pants" extra: Very liberal in interpreting a single prime as an
      # apostrophe; e.g. ignores the fact that "round", "bout", "twer", and
      # "twixt" can be written without an initial apostrophe. This is fine because
      # using scare quotes (single quotation marks) is rare.
      _apostrophe_year_re = re.compile(r"'(\d\d)(?=(\s|,|;|\.|\?|!|$))")
      _contractions = ["tis", "twas", "twer", "neath", "o", "n",
          "round", "bout", "twixt", "nuff", "fraid", "sup"]
      def _do_smart_contractions(self, text):
          text = self._apostrophe_year_re.sub(r"&#8217;\1", text)
          for c in self._contractions:
              text = text.replace("'%s" % c, "&#8217;%s" % c)
              text = text.replace("'%s" % c.capitalize(),
                  "&#8217;%s" % c.capitalize())
          return text
  
      # Substitute double-quotes before single-quotes.
      _opening_single_quote_re = re.compile(r"(?<!\S)'(?=\S)")
      _opening_double_quote_re = re.compile(r'(?<!\S)"(?=\S)')
      _closing_single_quote_re = re.compile(r"(?<=\S)'")
      _closing_double_quote_re = re.compile(r'(?<=\S)"(?=(\s|,|;|\.|\?|!|$))')
      def _do_smart_punctuation(self, text):
          """Fancifies 'single quotes', "double quotes", and apostrophes.
          Converts --, ---, and ... into en dashes, em dashes, and ellipses.
  
          Inspiration is: <http://daringfireball.net/projects/smartypants/>
          See "test/tm-cases/smarty_pants.text" for a full discussion of the
          support here and
          <http://code.google.com/p/python-markdown2/issues/detail?id=42> for a
          discussion of some diversion from the original SmartyPants.
          """
          if "'" in text: # guard for perf
              text = self._do_smart_contractions(text)
              text = self._opening_single_quote_re.sub("&#8216;", text)
              text = self._closing_single_quote_re.sub("&#8217;", text)
  
          if '"' in text: # guard for perf
              text = self._opening_double_quote_re.sub("&#8220;", text)
              text = self._closing_double_quote_re.sub("&#8221;", text)
  
          text = text.replace("---", "&#8212;")
          text = text.replace("--", "&#8211;")
          text = text.replace("...", "&#8230;")
          text = text.replace(" . . . ", "&#8230;")
          text = text.replace(". . .", "&#8230;")
          return text
  
      _block_quote_re = re.compile(r'''
          (                           # Wrap whole match in \1
            (
              ^[ \t]*>[ \t]?          # '>' at the start of a line
                .+\n                  # rest of the first line
              (.+\n)*                 # subsequent consecutive lines
              \n*                     # blanks
            )+
          )
          ''', re.M | re.X)
      _bq_one_level_re = re.compile('^[ \t]*>[ \t]?', re.M);
  
      _html_pre_block_re = re.compile(r'(\s*<pre>.+?</pre>)', re.S)
      def _dedent_two_spaces_sub(self, match):
          return re.sub(r'(?m)^  ', '', match.group(1))
  
      def _block_quote_sub(self, match):
          bq = match.group(1)
          bq = self._bq_one_level_re.sub('', bq)  # trim one level of quoting
          bq = self._ws_only_line_re.sub('', bq)  # trim whitespace-only lines
          bq = self._run_block_gamut(bq)          # recurse
  
          bq = re.sub('(?m)^', '  ', bq)
          # These leading spaces screw with <pre> content, so we need to fix that:
          bq = self._html_pre_block_re.sub(self._dedent_two_spaces_sub, bq)
  
          return "<blockquote>\n%s\n</blockquote>\n\n" % bq
  
      def _do_block_quotes(self, text):
          if '>' not in text:
              return text
          return self._block_quote_re.sub(self._block_quote_sub, text)
  
      def _form_paragraphs(self, text):
          # Strip leading and trailing lines:
          text = text.strip('\n')
  
          # Wrap <p> tags.
          grafs = []
          for i, graf in enumerate(re.split(r"\n{2,}", text)):
              if graf in self.html_blocks:
                  # Unhashify HTML blocks
                  grafs.append(self.html_blocks[graf])
              else:
                  cuddled_list = None
                  if "cuddled-lists" in self.extras:
                      # Need to put back trailing '\n' for `_list_item_re`
                      # match at the end of the paragraph.
                      li = self._list_item_re.search(graf + '\n')
                      # Two of the same list marker in this paragraph: a likely
                      # candidate for a list cuddled to preceding paragraph
                      # text (issue 33). Note the `[-1]` is a quick way to
                      # consider numeric bullets (e.g. "1." and "2.") to be
                      # equal.
                      if (li and len(li.group(2)) <= 3 and li.group("next_marker")
                          and li.group("marker")[-1] == li.group("next_marker")[-1]):
                          start = li.start()
                          cuddled_list = self._do_lists(graf[start:]).rstrip("\n")
                          assert cuddled_list.startswith("<ul>") or cuddled_list.startswith("<ol>")
                          graf = graf[:start]
  
                  # Wrap <p> tags.
                  graf = self._run_span_gamut(graf)
                  grafs.append("<p>" + graf.lstrip(" \t") + "</p>")
  
                  if cuddled_list:
                      grafs.append(cuddled_list)
  
          return "\n\n".join(grafs)
  
      def _add_footnotes(self, text):
          if self.footnotes:
              footer = [
                  '<div class="footnotes">',
                  '<hr' + self.empty_element_suffix,
                  '<ol>',
              ]
              for i, id in enumerate(self.footnote_ids):
                  if i != 0:
                      footer.append('')
                  footer.append('<li id="fn-%s">' % id)
                  footer.append(self._run_block_gamut(self.footnotes[id]))
                  backlink = ('<a href="#fnref-%s" '
                      'class="footnoteBackLink" '
                      'title="Jump back to footnote %d in the text.">'
                      '&#8617;</a>' % (id, i+1))
                  if footer[-1].endswith("</p>"):
                      footer[-1] = footer[-1][:-len("</p>")] \
                          + '&nbsp;' + backlink + "</p>"
                  else:
                      footer.append("\n<p>%s</p>" % backlink)
                  footer.append('</li>')
              footer.append('</ol>')
              footer.append('</div>')
              return text + '\n\n' + '\n'.join(footer)
          else:
              return text
  
      # Ampersand-encoding based entirely on Nat Irons's Amputator MT plugin:
      #   http://bumppo.net/projects/amputator/
      _ampersand_re = re.compile(r'&(?!#?[xX]?(?:[0-9a-fA-F]+|\w+);)')
      _naked_lt_re = re.compile(r'<(?![a-z/?\$!])', re.I)
      _naked_gt_re = re.compile(r'''(?<![a-z0-9?!/'"-])>''', re.I)
  
      def _encode_amps_and_angles(self, text):
          # Smart processing for ampersands and angle brackets that need
          # to be encoded.
          text = self._ampersand_re.sub('&amp;', text)
  
          # Encode naked <'s
          text = self._naked_lt_re.sub('&lt;', text)
  
          # Encode naked >'s
          # Note: Other markdown implementations (e.g. Markdown.pl, PHP
          # Markdown) don't do this.
          text = self._naked_gt_re.sub('&gt;', text)
          return text
  
      def _encode_backslash_escapes(self, text):
          for ch, escape in list(self._escape_table.items()):
              text = text.replace("\\"+ch, escape)
          return text
  
      _auto_link_re = re.compile(r'<((https?|ftp):[^\'">\s]+)>', re.I)
      def _auto_link_sub(self, match):
          g1 = match.group(1)
          return '<a href="%s">%s</a>' % (g1, g1)
  
      _auto_email_link_re = re.compile(r"""
            <
             (?:mailto:)?
            (
                [-.\w]+
                \@
                [-\w]+(\.[-\w]+)*\.[a-z]+
            )
            >
          """, re.I | re.X | re.U)
      def _auto_email_link_sub(self, match):
          return self._encode_email_address(
              self._unescape_special_chars(match.group(1)))
  
      def _do_auto_links(self, text):
          text = self._auto_link_re.sub(self._auto_link_sub, text)
          text = self._auto_email_link_re.sub(self._auto_email_link_sub, text)
          return text
  
      def _encode_email_address(self, addr):
          #  Input: an email address, e.g. "foo@example.com"
          #
          #  Output: the email address as a mailto link, with each character
          #      of the address encoded as either a decimal or hex entity, in
          #      the hopes of foiling most address harvesting spam bots. E.g.:
          #
          #    <a href="&#x6D;&#97;&#105;&#108;&#x74;&#111;:&#102;&#111;&#111;&#64;&#101;
          #       x&#x61;&#109;&#x70;&#108;&#x65;&#x2E;&#99;&#111;&#109;">&#102;&#111;&#111;
          #       &#64;&#101;x&#x61;&#109;&#x70;&#108;&#x65;&#x2E;&#99;&#111;&#109;</a>
          #
          #  Based on a filter by Matthew Wickline, posted to the BBEdit-Talk
          #  mailing list: <http://tinyurl.com/yu7ue>
          chars = [_xml_encode_email_char_at_random(ch)
                   for ch in "mailto:" + addr]
          # Strip the mailto: from the visible part.
          addr = '<a href="%s">%s</a>' \
                 % (''.join(chars), ''.join(chars[7:]))
          return addr
  
      def _do_link_patterns(self, text):
          """Caveat emptor: there isn't much guarding against link
          patterns being formed inside other standard Markdown links, e.g.
          inside a [link def][like this].
  
          Dev Notes: *Could* consider prefixing regexes with a negative
          lookbehind assertion to attempt to guard against this.
          """
          link_from_hash = {}
          for regex, repl in self.link_patterns:
              replacements = []
              for match in regex.finditer(text):
                  if hasattr(repl, "__call__"):
                      href = repl(match)
                  else:
                      href = match.expand(repl)
                  replacements.append((match.span(), href))
              for (start, end), href in reversed(replacements):
                  escaped_href = (
                      href.replace('"', '&quot;')  # b/c of attr quote
                          # To avoid markdown <em> and <strong>:
                          .replace('*', self._escape_table['*'])
                          .replace('_', self._escape_table['_']))
                  link = '<a href="%s">%s</a>' % (escaped_href, text[start:end])
                  hash = _hash_text(link)
                  link_from_hash[hash] = link
                  text = text[:start] + hash + text[end:]
          for hash, link in list(link_from_hash.items()):
              text = text.replace(hash, link)
          return text
  
      def _unescape_special_chars(self, text):
          # Swap back in all the special characters we've hidden.
          for ch, hash in list(self._escape_table.items()):
              text = text.replace(hash, ch)
          return text
  
      def _outdent(self, text):
          # Remove one level of line-leading tabs or spaces
          return self._outdent_re.sub('', text)
  
  
  class MarkdownWithExtras(Markdown):
      """A markdowner class that enables most extras:
  
      - footnotes
      - code-color (only has effect if 'pygments' Python module on path)
  
      These are not included:
      - pyshell (specific to Python-related documenting)
      - code-friendly (because it *disables* part of the syntax)
      - link-patterns (because you need to specify some actual
        link-patterns anyway)
      """
      extras = ["footnotes", "code-color"]
  
  
  #---- internal support functions
  
  class UnicodeWithAttrs(unicode):
      """A subclass of unicode used for the return value of conversion to
      possibly attach some attributes. E.g. the "toc_html" attribute when
      the "toc" extra is used.
      """
      metadata = None
      _toc = None
      def toc_html(self):
          """Return the HTML for the current TOC.
  
          This expects the `_toc` attribute to have been set on this instance.
          """
          if self._toc is None:
              return None
  
          def indent():
              return '  ' * (len(h_stack) - 1)
          lines = []
          h_stack = [0]   # stack of header-level numbers
          for level, id, name in self._toc:
              if level > h_stack[-1]:
                  lines.append("%s<ul>" % indent())
                  h_stack.append(level)
              elif level == h_stack[-1]:
                  lines[-1] += "</li>"
              else:
                  while level < h_stack[-1]:
                      h_stack.pop()
                      if not lines[-1].endswith("</li>"):
                          lines[-1] += "</li>"
                      lines.append("%s</ul></li>" % indent())
              lines.append('%s<li><a href="#%s">%s</a>' % (
                  indent(), id, name))
          while len(h_stack) > 1:
              h_stack.pop()
              if not lines[-1].endswith("</li>"):
                  lines[-1] += "</li>"
              lines.append("%s</ul>" % indent())
          return '\n'.join(lines) + '\n'
      toc_html = property(toc_html)
  
  ## {{{ http://code.activestate.com/recipes/577257/ (r1)
  _slugify_strip_re = re.compile(r'[^\w\s-]')
  _slugify_hyphenate_re = re.compile(r'[-\s]+')
  def _slugify(value):
      """
      Normalizes string, converts to lowercase, removes non-alpha characters,
      and converts spaces to hyphens.
  
      From Django's "django/template/defaultfilters.py".
      """
  
      try:
          import unicodedata
          value = unicodedata.normalize('NFKD', value)
      except ImportError:
          pass
      value = value.encode('ascii', 'ignore').decode()
      value = _slugify_strip_re.sub('', value).strip().lower()
      return _slugify_hyphenate_re.sub('-', value)
  ## end of http://code.activestate.com/recipes/577257/ }}}
  
  
  # From http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/52549
  def _curry(*args, **kwargs):
      function, args = args[0], args[1:]
      def result(*rest, **kwrest):
          combined = kwargs.copy()
          combined.update(kwrest)
          return function(*args + rest, **combined)
      return result
  
  # Recipe: regex_from_encoded_pattern (1.0)
  def _regex_from_encoded_pattern(s):
      """'foo'    -> re.compile(re.escape('foo'))
         '/foo/'  -> re.compile('foo')
         '/foo/i' -> re.compile('foo', re.I)
      """
      if s.startswith('/') and s.rfind('/') != 0:
          # Parse it: /PATTERN/FLAGS
          idx = s.rfind('/')
          pattern, flags_str = s[1:idx], s[idx+1:]
          flag_from_char = {
              "i": re.IGNORECASE,
              "l": re.LOCALE,
              "s": re.DOTALL,
              "m": re.MULTILINE,
              "u": re.UNICODE,
          }
          flags = 0
          for char in flags_str:
              try:
                  flags |= flag_from_char[char]
              except KeyError:
                  raise ValueError("unsupported regex flag: '%s' in '%s' "
                                   "(must be one of '%s')"
                                   % (char, s, ''.join(list(flag_from_char.keys()))))
          return re.compile(s[1:idx], flags)
      else: # not an encoded regex
          return re.compile(re.escape(s))
  
  # Recipe: dedent (0.1.2)
  def _dedentlines(lines, tabsize=8, skip_first_line=False):
      """_dedentlines(lines, tabsize=8, skip_first_line=False) -> dedented lines
  
          "lines" is a list of lines to dedent.
          "tabsize" is the tab width to use for indent width calculations.
          "skip_first_line" is a boolean indicating if the first line should
              be skipped for calculating the indent width and for dedenting.
              This is sometimes useful for docstrings and similar.
  
      Same as dedent() except operates on a sequence of lines. Note: the
      lines list is modified **in-place**.
      """
      DEBUG = False
      if DEBUG:
          print("dedent: dedent(..., tabsize=%d, skip_first_line=%r)"\
                % (tabsize, skip_first_line))
      indents = []
      margin = None
      for i, line in enumerate(lines):
          if i == 0 and skip_first_line: continue
          indent = 0
          for ch in line:
              if ch == ' ':
                  indent += 1
              elif ch == '\t':
                  indent += tabsize - (indent % tabsize)
              elif ch in '\r\n':
                  continue # skip all-whitespace lines
              else:
                  break
          else:
              continue # skip all-whitespace lines
          if DEBUG: print("dedent: indent=%d: %r" % (indent, line))
          if margin is None:
              margin = indent
          else:
              margin = min(margin, indent)
      if DEBUG: print("dedent: margin=%r" % margin)
  
      if margin is not None and margin > 0:
          for i, line in enumerate(lines):
              if i == 0 and skip_first_line: continue
              removed = 0
              for j, ch in enumerate(line):
                  if ch == ' ':
                      removed += 1
                  elif ch == '\t':
                      removed += tabsize - (removed % tabsize)
                  elif ch in '\r\n':
                      if DEBUG: print("dedent: %r: EOL -> strip up to EOL" % line)
                      lines[i] = lines[i][j:]
                      break
                  else:
                      raise ValueError("unexpected non-whitespace char %r in "
                                       "line %r while removing %d-space margin"
                                       % (ch, line, margin))
                  if DEBUG:
                      print("dedent: %r: %r -> removed %d/%d"\
                            % (line, ch, removed, margin))
                  if removed == margin:
                      lines[i] = lines[i][j+1:]
                      break
                  elif removed > margin:
                      lines[i] = ' '*(removed-margin) + lines[i][j+1:]
                      break
              else:
                  if removed:
                      lines[i] = lines[i][removed:]
      return lines
  
  def _dedent(text, tabsize=8, skip_first_line=False):
      """_dedent(text, tabsize=8, skip_first_line=False) -> dedented text
  
          "text" is the text to dedent.
          "tabsize" is the tab width to use for indent width calculations.
          "skip_first_line" is a boolean indicating if the first line should
              be skipped for calculating the indent width and for dedenting.
              This is sometimes useful for docstrings and similar.
  
      textwrap.dedent(s), but don't expand tabs to spaces
      """
      lines = text.splitlines(1)
      _dedentlines(lines, tabsize=tabsize, skip_first_line=skip_first_line)
      return ''.join(lines)
  
  
  class _memoized(object):
     """Decorator that caches a function's return value each time it is called.
     If called later with the same arguments, the cached value is returned, and
     not re-evaluated.
  
     http://wiki.python.org/moin/PythonDecoratorLibrary
     """
     def __init__(self, func):
        self.func = func
        self.cache = {}
     def __call__(self, *args):
        try:
           return self.cache[args]
        except KeyError:
           self.cache[args] = value = self.func(*args)
           return value
        except TypeError:
           # uncachable -- for instance, passing a list as an argument.
           # Better to not cache than to blow up entirely.
           return self.func(*args)
     def __repr__(self):
        """Return the function's docstring."""
        return self.func.__doc__
  
  
  def _xml_oneliner_re_from_tab_width(tab_width):
      """Standalone XML processing instruction regex."""
      return re.compile(r"""
          (?:
              (?<=\n\n)       # Starting after a blank line
              |               # or
              \A\n?           # the beginning of the doc
          )
          (                           # save in $1
              [ ]{0,%d}
              (?:
                  <\?\w+\b\s+.*?\?>   # XML processing instruction
                  |
                  <\w+:\w+\b\s+.*?/>  # namespaced single tag
              )
              [ \t]*
              (?=\n{2,}|\Z)       # followed by a blank line or end of document
          )
          """ % (tab_width - 1), re.X)
  _xml_oneliner_re_from_tab_width = _memoized(_xml_oneliner_re_from_tab_width)
  
  def _hr_tag_re_from_tab_width(tab_width):
       return re.compile(r"""
          (?:
              (?<=\n\n)       # Starting after a blank line
              |               # or
              \A\n?           # the beginning of the doc
          )
          (                       # save in \1
              [ ]{0,%d}
              <(hr)               # start tag = \2
              \b                  # word break
              ([^<>])*?           #
              /?>                 # the matching end tag
              [ \t]*
              (?=\n{2,}|\Z)       # followed by a blank line or end of document
          )
          """ % (tab_width - 1), re.X)
  _hr_tag_re_from_tab_width = _memoized(_hr_tag_re_from_tab_width)
  
  
  def _xml_escape_attr(attr, skip_single_quote=True):
      """Escape the given string for use in an HTML/XML tag attribute.
  
      By default this doesn't bother with escaping `'` to `&#39;`, presuming that
      the tag attribute is surrounded by double quotes.
      """
      escaped = (attr
          .replace('&', '&amp;')
          .replace('"', '&quot;')
          .replace('<', '&lt;')
          .replace('>', '&gt;'))
      if not skip_single_quote:
          escaped = escaped.replace("'", "&#39;")
      return escaped
  
  
  def _xml_encode_email_char_at_random(ch):
      r = random()
      # Roughly 10% raw, 45% hex, 45% dec.
      # '@' *must* be encoded. I [John Gruber] insist.
      # Issue 26: '_' must be encoded.
      if r > 0.9 and ch not in "@_":
          return ch
      elif r < 0.45:
          # The [1:] is to drop leading '0': 0x63 -> x63
          return '&#%s;' % hex(ord(ch))[1:]
      else:
          return '&#%s;' % ord(ch)
  
  
  
  #---- mainline
  
  class _NoReflowFormatter(optparse.IndentedHelpFormatter):
      """An optparse formatter that does NOT reflow the description."""
      def format_description(self, description):
          return description or ""
  
  def _test():
      import doctest
      doctest.testmod()
  
  def main(argv=None):
      if argv is None:
          argv = sys.argv
      if not logging.root.handlers:
          logging.basicConfig()
  
      usage = "usage: %prog [PATHS...]"
      version = "%prog "+__version__
      parser = optparse.OptionParser(prog="markdown2", usage=usage,
          version=version, description=cmdln_desc,
          formatter=_NoReflowFormatter())
      parser.add_option("-v", "--verbose", dest="log_level",
                        action="store_const", const=logging.DEBUG,
                        help="more verbose output")
      parser.add_option("--encoding",
                        help="specify encoding of text content")
      parser.add_option("--html4tags", action="store_true", default=False,
                        help="use HTML 4 style for empty element tags")
      parser.add_option("-s", "--safe", metavar="MODE", dest="safe_mode",
                        help="sanitize literal HTML: 'escape' escapes "
                             "HTML meta chars, 'replace' replaces with an "
                             "[HTML_REMOVED] note")
      parser.add_option("-x", "--extras", action="append",
                        help="Turn on specific extra features (not part of "
                             "the core Markdown spec). See above.")
      parser.add_option("--use-file-vars",
                        help="Look for and use Emacs-style 'markdown-extras' "
                             "file var to turn on extras. See "
                             "<https://github.com/trentm/python-markdown2/wiki/Extras>")
      parser.add_option("--link-patterns-file",
                        help="path to a link pattern file")
      parser.add_option("--self-test", action="store_true",
                        help="run internal self-tests (some doctests)")
      parser.add_option("--compare", action="store_true",
                        help="run against Markdown.pl as well (for testing)")
      parser.set_defaults(log_level=logging.INFO, compare=False,
                          encoding="utf-8", safe_mode=None, use_file_vars=False)
      opts, paths = parser.parse_args()
      log.setLevel(opts.log_level)
  
      if opts.self_test:
          return _test()
  
      if opts.extras:
          extras = {}
          for s in opts.extras:
              splitter = re.compile("[,;: ]+")
              for e in splitter.split(s):
                  if '=' in e:
                      ename, earg = e.split('=', 1)
                      try:
                          earg = int(earg)
                      except ValueError:
                          pass
                  else:
                      ename, earg = e, None
                  extras[ename] = earg
      else:
          extras = None
  
      if opts.link_patterns_file:
          link_patterns = []
          f = open(opts.link_patterns_file)
          try:
              for i, line in enumerate(f.readlines()):
                  if not line.strip(): continue
                  if line.lstrip().startswith("#"): continue
                  try:
                      pat, href = line.rstrip().rsplit(None, 1)
                  except ValueError:
                      raise MarkdownError("%s:%d: invalid link pattern line: %r"
                                          % (opts.link_patterns_file, i+1, line))
                  link_patterns.append(
                      (_regex_from_encoded_pattern(pat), href))
          finally:
              f.close()
      else:
          link_patterns = None
  
      from os.path import join, dirname, abspath, exists
      markdown_pl = join(dirname(dirname(abspath(__file__))), "test",
                         "Markdown.pl")
      if not paths:
          paths = ['-']
      for path in paths:
          if path == '-':
              text = sys.stdin.read()
          else:
              fp = codecs.open(path, 'r', opts.encoding)
              text = fp.read()
              fp.close()
          if opts.compare:
              from subprocess import Popen, PIPE
              print("==== Markdown.pl ====")
              p = Popen('perl %s' % markdown_pl, shell=True, stdin=PIPE, stdout=PIPE, close_fds=True)
              p.stdin.write(text.encode('utf-8'))
              p.stdin.close()
              perl_html = p.stdout.read().decode('utf-8')
              if py3:
                  sys.stdout.write(perl_html)
              else:
                  sys.stdout.write(perl_html.encode(
                      sys.stdout.encoding or "utf-8", 'xmlcharrefreplace'))
              print("==== markdown2.py ====")
          html = markdown(text,
              html4tags=opts.html4tags,
              safe_mode=opts.safe_mode,
              extras=extras, link_patterns=link_patterns,
              use_file_vars=opts.use_file_vars)
          if py3:
              sys.stdout.write(html)
          else:
              sys.stdout.write(html.encode(
                  sys.stdout.encoding or "utf-8", 'xmlcharrefreplace'))
          if extras and "toc" in extras:
              log.debug("toc_html: " +
                  html.toc_html.encode(sys.stdout.encoding or "utf-8", 'xmlcharrefreplace'))
          if opts.compare:
              test_dir = join(dirname(dirname(abspath(__file__))), "test")
              if exists(join(test_dir, "test_markdown2.py")):
                  sys.path.insert(0, test_dir)
                  from test_markdown2 import norm_html_from_html
                  norm_html = norm_html_from_html(html)
                  norm_perl_html = norm_html_from_html(perl_html)
              else:
                  norm_html = html
                  norm_perl_html = perl_html
              print("==== match? %r ====" % (norm_perl_html == norm_html))
  
  
  if __name__ == "__main__":
      sys.exit( main(sys.argv) )
  