moth/lib/python/mistune.py

# coding: utf-8
"""mistune
    ~~~~~~~

    The fastest markdown parser in pure Python with renderer feature.

    Copyright (c) 2014 - 2015, Hsiaoming Yang

    All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions
    are met:

    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.

    * Redistributions in binary form must reproduce the above
      copyright notice, this list of conditions and the following
      disclaimer in the documentation and/or other materials provided
      with the distribution.

    * Neither the name of the creator nor the names of its
      contributors may be used to endorse or promote products derived
      from this software without specific prior written permission.


    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
    CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
    INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
    MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
    DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS
    BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
    EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
    TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
    ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
    TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
    THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
    SUCH DAMAGE.
"""

import re
import inspect

__version__ = '0.7.3'
__author__ = 'Hsiaoming Yang <me@lepture.com>'
__all__ = [
    'BlockGrammar', 'BlockLexer',
    'InlineGrammar', 'InlineLexer',
    'Renderer', 'Markdown',
    'markdown', 'escape',
]


_key_pattern = re.compile(r'\s+')
_nonalpha_pattern = re.compile(r'\W')
_escape_pattern = re.compile(r'&(?!#?\w+;)')
_newline_pattern = re.compile(r'\r\n|\r')
_block_quote_leading_pattern = re.compile(r'^ *> ?', flags=re.M)
_block_code_leading_pattern = re.compile(r'^ {4}', re.M)
_inline_tags = [
    'a', 'em', 'strong', 'small', 's', 'cite', 'q', 'dfn', 'abbr', 'data',
    'time', 'code', 'var', 'samp', 'kbd', 'sub', 'sup', 'i', 'b', 'u', 'mark',
    'ruby', 'rt', 'rp', 'bdi', 'bdo', 'span', 'br', 'wbr', 'ins', 'del',
    'img', 'font',
]
_pre_tags = ['pre', 'script', 'style']
_valid_end = r'(?!:/|[^\w\s@]*@)\b'
_valid_attr = r'''\s*[a-zA-Z\-](?:\=(?:"[^"]*"|'[^']*'|\d+))*'''
_block_tag = r'(?!(?:%s)\b)\w+%s' % ('|'.join(_inline_tags), _valid_end)
_scheme_blacklist = ('javascript:', 'vbscript:')


def _pure_pattern(regex):
    pattern = regex.pattern
    if pattern.startswith('^'):
        pattern = pattern[1:]
    return pattern


def _keyify(key):
    return _key_pattern.sub(' ', key.lower())


def escape(text, quote=False, smart_amp=True):
    """Replace special characters "&", "<" and ">" to HTML-safe sequences.

    The original cgi.escape will always escape "&", but you can control
    this one for a smart escape amp.

    :param quote: if set to True, " and ' will be escaped.
    :param smart_amp: if set to False, & will always be escaped.
    """
    if smart_amp:
        text = _escape_pattern.sub('&amp;', text)
    else:
        text = text.replace('&', '&amp;')
    text = text.replace('<', '&lt;')
    text = text.replace('>', '&gt;')
    if quote:
        text = text.replace('"', '&quot;')
        text = text.replace("'", '&#39;')
    return text


def escape_link(url):
    """Remove dangerous URL schemes like javascript: and escape afterwards."""
    lower_url = url.lower().strip('\x00\x1a \n\r\t')
    for scheme in _scheme_blacklist:
        if lower_url.startswith(scheme):
            return ''
    return escape(url, quote=True, smart_amp=False)


def preprocessing(text, tab=4):
    text = _newline_pattern.sub('\n', text)
    text = text.expandtabs(tab)
    text = text.replace('\u00a0', ' ')
    text = text.replace('\u2424', '\n')
    pattern = re.compile(r'^ +$', re.M)
    return pattern.sub('', text)


class BlockGrammar(object):
    """Grammars for block level tokens."""

    def_links = re.compile(
        r'^ *\[([^^\]]+)\]: *'  # [key]:
        r'<?([^\s>]+)>?'  # <link> or link
        r'(?: +["(]([^\n]+)[")])? *(?:\n+|$)'
    )
    def_footnotes = re.compile(
        r'^\[\^([^\]]+)\]: *('
        r'[^\n]*(?:\n+|$)'  # [^key]:
        r'(?: {1,}[^\n]*(?:\n+|$))*'
        r')'
    )

    newline = re.compile(r'^\n+')
    block_code = re.compile(r'^( {4}[^\n]+\n*)+')
    fences = re.compile(
        r'^ *(`{3,}|~{3,}) *(\S+)? *\n'  # ```lang
        r'([\s\S]+?)\s*'
        r'\1 *(?:\n+|$)'  # ```
    )
    hrule = re.compile(r'^ {0,3}[-*_](?: *[-*_]){2,} *(?:\n+|$)')
    heading = re.compile(r'^ *(#{1,6}) *([^\n]+?) *#* *(?:\n+|$)')
    lheading = re.compile(r'^([^\n]+)\n *(=|-)+ *(?:\n+|$)')
    block_quote = re.compile(r'^( *>[^\n]+(\n[^\n]+)*\n*)+')
    list_block = re.compile(
        r'^( *)([*+-]|\d+\.) [\s\S]+?'
        r'(?:'
        r'\n+(?=\1?(?:[-*_] *){3,}(?:\n+|$))'  # hrule
        r'|\n+(?=%s)'  # def links
        r'|\n+(?=%s)'  # def footnotes
        r'|\n{2,}'
        r'(?! )'
        r'(?!\1(?:[*+-]|\d+\.) )\n*'
        r'|'
        r'\s*$)' % (
            _pure_pattern(def_links),
            _pure_pattern(def_footnotes),
        )
    )
    list_item = re.compile(
        r'^(( *)(?:[*+-]|\d+\.) [^\n]*'
        r'(?:\n(?!\2(?:[*+-]|\d+\.) )[^\n]*)*)',
        flags=re.M
    )
    list_bullet = re.compile(r'^ *(?:[*+-]|\d+\.) +')
    paragraph = re.compile(
        r'^((?:[^\n]+\n?(?!'
        r'%s|%s|%s|%s|%s|%s|%s|%s|%s'
        r'))+)\n*' % (
            _pure_pattern(fences).replace(r'\1', r'\2'),
            _pure_pattern(list_block).replace(r'\1', r'\3'),
            _pure_pattern(hrule),
            _pure_pattern(heading),
            _pure_pattern(lheading),
            _pure_pattern(block_quote),
            _pure_pattern(def_links),
            _pure_pattern(def_footnotes),
            '<' + _block_tag,
        )
    )
    block_html = re.compile(
        r'^ *(?:%s|%s|%s) *(?:\n{2,}|\s*$)' % (
            r'<!--[\s\S]*?-->',
            r'<(%s)((?:%s)*?)>([\s\S]*?)<\/\1>' % (_block_tag, _valid_attr),
            r'<%s(?:%s)*?\s*\/?>' % (_block_tag, _valid_attr),
        )
    )
    table = re.compile(
        r'^ *\|(.+)\n *\|( *[-:]+[-| :]*)\n((?: *\|.*(?:\n|$))*)\n*'
    )
    nptable = re.compile(
        r'^ *(\S.*\|.*)\n *([-:]+ *\|[-| :]*)\n((?:.*\|.*(?:\n|$))*)\n*'
    )
    text = re.compile(r'^[^\n]+')


class BlockLexer(object):
    """Block level lexer for block grammars."""
    grammar_class = BlockGrammar

    default_rules = [
        'newline', 'hrule', 'block_code', 'fences', 'heading',
        'nptable', 'lheading', 'block_quote',
        'list_block', 'block_html', 'def_links',
        'def_footnotes', 'table', 'paragraph', 'text'
    ]

    list_rules = (
        'newline', 'block_code', 'fences', 'lheading', 'hrule',
        'block_quote', 'list_block', 'block_html', 'text',
    )

    footnote_rules = (
        'newline', 'block_code', 'fences', 'heading',
        'nptable', 'lheading', 'hrule', 'block_quote',
        'list_block', 'block_html', 'table', 'paragraph', 'text'
    )

    def __init__(self, rules=None, **kwargs):
        self.tokens = []
        self.def_links = {}
        self.def_footnotes = {}

        if not rules:
            rules = self.grammar_class()

        self.rules = rules

    def __call__(self, text, rules=None):
        return self.parse(text, rules)

    def parse(self, text, rules=None):
        text = text.rstrip('\n')

        if not rules:
            rules = self.default_rules

        def manipulate(text):
            for key in rules:
                rule = getattr(self.rules, key)
                m = rule.match(text)
                if not m:
                    continue
                getattr(self, 'parse_%s' % key)(m)
                return m
            return False  # pragma: no cover

        while text:
            m = manipulate(text)
            if m is not False:
                text = text[len(m.group(0)):]
                continue
            if text:  # pragma: no cover
                raise RuntimeError('Infinite loop at: %s' % text)
        return self.tokens

    def parse_newline(self, m):
        length = len(m.group(0))
        if length > 1:
            self.tokens.append({'type': 'newline'})

    def parse_block_code(self, m):
        # clean leading whitespace
        code = _block_code_leading_pattern.sub('', m.group(0))
        self.tokens.append({
            'type': 'code',
            'lang': None,
            'text': code,
        })

    def parse_fences(self, m):
        self.tokens.append({
            'type': 'code',
            'lang': m.group(2),
            'text': m.group(3),
        })

    def parse_heading(self, m):
        self.tokens.append({
            'type': 'heading',
            'level': len(m.group(1)),
            'text': m.group(2),
        })

    def parse_lheading(self, m):
        """Parse setext heading."""
        self.tokens.append({
            'type': 'heading',
            'level': 1 if m.group(2) == '=' else 2,
            'text': m.group(1),
        })

    def parse_hrule(self, m):
        self.tokens.append({'type': 'hrule'})

    def parse_list_block(self, m):
        bull = m.group(2)
        self.tokens.append({
            'type': 'list_start',
            'ordered': '.' in bull,
        })
        cap = m.group(0)
        self._process_list_item(cap, bull)
        self.tokens.append({'type': 'list_end'})

    def _process_list_item(self, cap, bull):
        cap = self.rules.list_item.findall(cap)

        _next = False
        length = len(cap)

        for i in range(length):
            item = cap[i][0]

            # remove the bullet
            space = len(item)
            item = self.rules.list_bullet.sub('', item)

            # outdent
            if '\n ' in item:
                space = space - len(item)
                pattern = re.compile(r'^ {1,%d}' % space, flags=re.M)
                item = pattern.sub('', item)

            # determine whether item is loose or not
            loose = _next
            if not loose and re.search(r'\n\n(?!\s*$)', item):
                loose = True

            rest = len(item)
            if i != length - 1 and rest:
                _next = item[rest - 1] == '\n'
                if not loose:
                    loose = _next

            if loose:
                t = 'loose_item_start'
            else:
                t = 'list_item_start'

            self.tokens.append({'type': t})
            # recurse
            self.parse(item, self.list_rules)
            self.tokens.append({'type': 'list_item_end'})

    def parse_block_quote(self, m):
        self.tokens.append({'type': 'block_quote_start'})
        # clean leading >
        cap = _block_quote_leading_pattern.sub('', m.group(0))
        self.parse(cap)
        self.tokens.append({'type': 'block_quote_end'})

    def parse_def_links(self, m):
        key = _keyify(m.group(1))
        self.def_links[key] = {
            'link': m.group(2),
            'title': m.group(3),
        }

    def parse_def_footnotes(self, m):
        key = _keyify(m.group(1))
        if key in self.def_footnotes:
            # footnote is already defined
            return

        self.def_footnotes[key] = 0

        self.tokens.append({
            'type': 'footnote_start',
            'key': key,
        })

        text = m.group(2)

        if '\n' in text:
            lines = text.split('\n')
            whitespace = None
            for line in lines[1:]:
                space = len(line) - len(line.lstrip())
                if space and (not whitespace or space < whitespace):
                    whitespace = space
            newlines = [lines[0]]
            for line in lines[1:]:
                newlines.append(line[whitespace:])
            text = '\n'.join(newlines)

        self.parse(text, self.footnote_rules)

        self.tokens.append({
            'type': 'footnote_end',
            'key': key,
        })

    def parse_table(self, m):
        item = self._process_table(m)

        cells = re.sub(r'(?: *\| *)?\n$', '', m.group(3))
        cells = cells.split('\n')
        for i, v in enumerate(cells):
            v = re.sub(r'^ *\| *| *\| *$', '', v)
            cells[i] = re.split(r' *\| *', v)

        item['cells'] = cells
        self.tokens.append(item)

    def parse_nptable(self, m):
        item = self._process_table(m)

        cells = re.sub(r'\n$', '', m.group(3))
        cells = cells.split('\n')
        for i, v in enumerate(cells):
            cells[i] = re.split(r' *\| *', v)

        item['cells'] = cells
        self.tokens.append(item)

    def _process_table(self, m):
        header = re.sub(r'^ *| *\| *$', '', m.group(1))
        header = re.split(r' *\| *', header)
        align = re.sub(r' *|\| *$', '', m.group(2))
        align = re.split(r' *\| *', align)

        for i, v in enumerate(align):
            if re.search(r'^ *-+: *$', v):
                align[i] = 'right'
            elif re.search(r'^ *:-+: *$', v):
                align[i] = 'center'
            elif re.search(r'^ *:-+ *$', v):
                align[i] = 'left'
            else:
                align[i] = None

        item = {
            'type': 'table',
            'header': header,
            'align': align,
        }
        return item

    def parse_block_html(self, m):
        tag = m.group(1)
        if not tag:
            text = m.group(0)
            self.tokens.append({
                'type': 'close_html',
                'text': text
            })
        else:
            attr = m.group(2)
            text = m.group(3)
            self.tokens.append({
                'type': 'open_html',
                'tag': tag,
                'extra': attr,
                'text': text
            })

    def parse_paragraph(self, m):
        text = m.group(1).rstrip('\n')
        self.tokens.append({'type': 'paragraph', 'text': text})

    def parse_text(self, m):
        text = m.group(0)
        self.tokens.append({'type': 'text', 'text': text})


class InlineGrammar(object):
    """Grammars for inline level tokens."""

    escape = re.compile(r'^\\([\\`*{}\[\]()#+\-.!_>~|])')  # \* \+ \! ....
    inline_html = re.compile(
        r'^(?:%s|%s|%s)' % (
            r'<!--[\s\S]*?-->',
            r'<(\w+%s)((?:%s)*?)\s*>([\s\S]*?)<\/\1>' % (_valid_end, _valid_attr),
            r'<\w+%s(?:%s)*?\s*\/?>' % (_valid_end, _valid_attr),
        )
    )
    autolink = re.compile(r'^<([^ >]+(@|:)[^ >]+)>')
    link = re.compile(
        r'^!?\[('
        r'(?:\[[^^\]]*\]|[^\[\]]|\](?=[^\[]*\]))*'
        r')\]\('
        r'''\s*(<)?([\s\S]*?)(?(2)>)(?:\s+['"]([\s\S]*?)['"])?\s*'''
        r'\)'
    )
    reflink = re.compile(
        r'^!?\[('
        r'(?:\[[^^\]]*\]|[^\[\]]|\](?=[^\[]*\]))*'
        r')\]\s*\[([^^\]]*)\]'
    )
    nolink = re.compile(r'^!?\[((?:\[[^\]]*\]|[^\[\]])*)\]')
    url = re.compile(r'''^(https?:\/\/[^\s<]+[^<.,:;"')\]\s])''')
    double_emphasis = re.compile(
        r'^_{2}([\s\S]+?)_{2}(?!_)'  # __word__
        r'|'
        r'^\*{2}([\s\S]+?)\*{2}(?!\*)'  # **word**
    )
    emphasis = re.compile(
        r'^\b_((?:__|[^_])+?)_\b'  # _word_
        r'|'
        r'^\*((?:\*\*|[^\*])+?)\*(?!\*)'  # *word*
    )
    code = re.compile(r'^(`+)\s*([\s\S]*?[^`])\s*\1(?!`)')  # `code`
    linebreak = re.compile(r'^ {2,}\n(?!\s*$)')
    strikethrough = re.compile(r'^~~(?=\S)([\s\S]*?\S)~~')  # ~~word~~
    footnote = re.compile(r'^\[\^([^\]]+)\]')
    text = re.compile(r'^[\s\S]+?(?=[\\<!\[_*`~]|https?://| {2,}\n|$)')

    def hard_wrap(self):
        """Grammar for hard wrap linebreak. You don't need to add two
        spaces at the end of a line.
        """
        self.linebreak = re.compile(r'^ *\n(?!\s*$)')
        self.text = re.compile(
            r'^[\s\S]+?(?=[\\<!\[_*`~]|https?://| *\n|$)'
        )


class InlineLexer(object):
    """Inline level lexer for inline grammars."""
    grammar_class = InlineGrammar

    default_rules = [
        'escape', 'inline_html', 'autolink', 'url',
        'footnote', 'link', 'reflink', 'nolink',
        'double_emphasis', 'emphasis', 'code',
        'linebreak', 'strikethrough', 'text',
    ]
    inline_html_rules = [
        'escape', 'autolink', 'url', 'link', 'reflink',
        'nolink', 'double_emphasis', 'emphasis', 'code',
        'linebreak', 'strikethrough', 'text',
    ]

    def __init__(self, renderer, rules=None, **kwargs):
        self.renderer = renderer
        self.links = {}
        self.footnotes = {}
        self.footnote_index = 0

        if not rules:
            rules = self.grammar_class()

        kwargs.update(self.renderer.options)
        if kwargs.get('hard_wrap'):
            rules.hard_wrap()

        self.rules = rules

        self._in_link = False
        self._in_footnote = False
        self._parse_inline_html = kwargs.get('parse_inline_html')

    def __call__(self, text, rules=None):
        return self.output(text, rules)

    def setup(self, links, footnotes):
        self.footnote_index = 0
        self.links = links or {}
        self.footnotes = footnotes or {}

    def output(self, text, rules=None):
        text = text.rstrip('\n')
        if not rules:
            rules = list(self.default_rules)

        if self._in_footnote and 'footnote' in rules:
            rules.remove('footnote')

        output = self.renderer.placeholder()

        def manipulate(text):
            for key in rules:
                pattern = getattr(self.rules, key)
                m = pattern.match(text)
                if not m:
                    continue
                self.line_match = m
                out = getattr(self, 'output_%s' % key)(m)
                if out is not None:
                    return m, out
            return False  # pragma: no cover

        self.line_started = False
        while text:
            ret = manipulate(text)
            self.line_started = True
            if ret is not False:
                m, out = ret
                output += out
                text = text[len(m.group(0)):]
                continue
            if text:  # pragma: no cover
                raise RuntimeError('Infinite loop at: %s' % text)

        return output

    def output_escape(self, m):
        text = m.group(1)
        return self.renderer.escape(text)

    def output_autolink(self, m):
        link = m.group(1)
        if m.group(2) == '@':
            is_email = True
        else:
            is_email = False
        return self.renderer.autolink(link, is_email)

    def output_url(self, m):
        link = m.group(1)
        if self._in_link:
            return self.renderer.text(link)
        return self.renderer.autolink(link, False)

    def output_inline_html(self, m):
        tag = m.group(1)
        if self._parse_inline_html and tag in _inline_tags:
            text = m.group(3)
            if tag == 'a':
                self._in_link = True
                text = self.output(text, rules=self.inline_html_rules)
                self._in_link = False
            else:
                text = self.output(text, rules=self.inline_html_rules)
            extra = m.group(2) or ''
            html = '<%s%s>%s</%s>' % (tag, extra, text, tag)
        else:
            html = m.group(0)
        return self.renderer.inline_html(html)

    def output_footnote(self, m):
        key = _keyify(m.group(1))
        if key not in self.footnotes:
            return None
        if self.footnotes[key]:
            return None
        self.footnote_index += 1
        self.footnotes[key] = self.footnote_index
        return self.renderer.footnote_ref(key, self.footnote_index)

    def output_link(self, m):
        return self._process_link(m, m.group(3), m.group(4))

    def output_reflink(self, m):
        key = _keyify(m.group(2) or m.group(1))
        if key not in self.links:
            return None
        ret = self.links[key]
        return self._process_link(m, ret['link'], ret['title'])

    def output_nolink(self, m):
        key = _keyify(m.group(1))
        if key not in self.links:
            return None
        ret = self.links[key]
        return self._process_link(m, ret['link'], ret['title'])

    def _process_link(self, m, link, title=None):
        line = m.group(0)
        text = m.group(1)
        if line[0] == '!':
            return self.renderer.image(link, title, text)

        self._in_link = True
        text = self.output(text)
        self._in_link = False
        return self.renderer.link(link, title, text)

    def output_double_emphasis(self, m):
        text = m.group(2) or m.group(1)
        text = self.output(text)
        return self.renderer.double_emphasis(text)

    def output_emphasis(self, m):
        text = m.group(2) or m.group(1)
        text = self.output(text)
        return self.renderer.emphasis(text)

    def output_code(self, m):
        text = m.group(2)
        return self.renderer.codespan(text)

    def output_linebreak(self, m):
        return self.renderer.linebreak()

    def output_strikethrough(self, m):
        text = self.output(m.group(1))
        return self.renderer.strikethrough(text)

    def output_text(self, m):
        text = m.group(0)
        return self.renderer.text(text)


class Renderer(object):
    """The default HTML renderer for rendering Markdown.
    """

    def __init__(self, **kwargs):
        self.options = kwargs

    def placeholder(self):
        """Returns the default, empty output value for the renderer.

        All renderer methods use the '+=' operator to append to this value.
        Default is a string so rendering HTML can build up a result string with
        the rendered Markdown.

        Can be overridden by Renderer subclasses to be types like an empty
        list, allowing the renderer to create a tree-like structure to
        represent the document (which can then be reprocessed later into a
        separate format like docx or pdf).
        """
        return ''

    def block_code(self, code, lang=None):
        """Rendering block level code. ``pre > code``.

        :param code: text content of the code block.
        :param lang: language of the given code.
        """
        code = code.rstrip('\n')
        if not lang:
            code = escape(code, smart_amp=False)
            return '<pre><code>%s\n</code></pre>\n' % code
        code = escape(code, quote=True, smart_amp=False)
        return '<pre><code class="lang-%s">%s\n</code></pre>\n' % (lang, code)

    def block_quote(self, text):
        """Rendering <blockquote> with the given text.

        :param text: text content of the blockquote.
        """
        return '<blockquote>%s\n</blockquote>\n' % text.rstrip('\n')

    def block_html(self, html):
        """Rendering block level pure html content.

        :param html: text content of the html snippet.
        """
        if self.options.get('skip_style') and \
           html.lower().startswith('<style'):
            return ''
        if self.options.get('escape'):
            return escape(html)
        return html

    def header(self, text, level, raw=None):
        """Rendering header/heading tags like ``<h1>`` ``<h2>``.

        :param text: rendered text content for the header.
        :param level: a number for the header level, for example: 1.
        :param raw: raw text content of the header.
        """
        return '<h%d>%s</h%d>\n' % (level, text, level)

    def hrule(self):
        """Rendering method for ``<hr>`` tag."""
        if self.options.get('use_xhtml'):
            return '<hr />\n'
        return '<hr>\n'

    def list(self, body, ordered=True):
        """Rendering list tags like ``<ul>`` and ``<ol>``.

        :param body: body contents of the list.
        :param ordered: whether this list is ordered or not.
        """
        tag = 'ul'
        if ordered:
            tag = 'ol'
        return '<%s>\n%s</%s>\n' % (tag, body, tag)

    def list_item(self, text):
        """Rendering list item snippet. Like ``<li>``."""
        return '<li>%s</li>\n' % text

    def paragraph(self, text):
        """Rendering paragraph tags. Like ``<p>``."""
        return '<p>%s</p>\n' % text.strip(' ')

    def table(self, header, body):
        """Rendering table element. Wrap header and body in it.

        :param header: header part of the table.
        :param body: body part of the table.
        """
        return (
            '<table>\n<thead>%s</thead>\n'
            '<tbody>\n%s</tbody>\n</table>\n'
        ) % (header, body)

    def table_row(self, content):
        """Rendering a table row. Like ``<tr>``.

        :param content: content of current table row.
        """
        return '<tr>\n%s</tr>\n' % content

    def table_cell(self, content, **flags):
        """Rendering a table cell. Like ``<th>`` ``<td>``.

        :param content: content of current table cell.
        :param header: whether this is header or not.
        :param align: align of current table cell.
        """
        if flags['header']:
            tag = 'th'
        else:
            tag = 'td'
        align = flags['align']
        if not align:
            return '<%s>%s</%s>\n' % (tag, content, tag)
        return '<%s style="text-align:%s">%s</%s>\n' % (
            tag, align, content, tag
        )

    def double_emphasis(self, text):
        """Rendering **strong** text.

        :param text: text content for emphasis.
        """
        return '<strong>%s</strong>' % text

    def emphasis(self, text):
        """Rendering *emphasis* text.

        :param text: text content for emphasis.
        """
        return '<em>%s</em>' % text

    def codespan(self, text):
        """Rendering inline `code` text.

        :param text: text content for inline code.
        """
        text = escape(text.rstrip(), smart_amp=False)
        return '<code>%s</code>' % text

    def linebreak(self):
        """Rendering line break like ``<br>``."""
        if self.options.get('use_xhtml'):
            return '<br />\n'
        return '<br>\n'

    def strikethrough(self, text):
        """Rendering ~~strikethrough~~ text.

        :param text: text content for strikethrough.
        """
        return '<del>%s</del>' % text

    def text(self, text):
        """Rendering unformatted text.

        :param text: text content.
        """
        return escape(text)

    def escape(self, text):
        """Rendering escape sequence.

        :param text: text content.
        """
        return escape(text)

    def autolink(self, link, is_email=False):
        """Rendering a given link or email address.

        :param link: link content or email address.
        :param is_email: whether this is an email or not.
        """
        text = link = escape(link)
        if is_email:
            link = 'mailto:%s' % link
        return '<a href="%s">%s</a>' % (link, text)

    def link(self, link, title, text):
        """Rendering a given link with content and title.

        :param link: href link for ``<a>`` tag.
        :param title: title content for `title` attribute.
        :param text: text content for description.
        """
        link = escape_link(link)
        if not title:
            return '<a href="%s">%s</a>' % (link, text)
        title = escape(title, quote=True)
        return '<a href="%s" title="%s">%s</a>' % (link, title, text)

    def image(self, src, title, text):
        """Rendering a image with title and text.

        :param src: source link of the image.
        :param title: title text of the image.
        :param text: alt text of the image.
        """
        src = escape_link(src)
        text = escape(text, quote=True)
        if title:
            title = escape(title, quote=True)
            html = '<img src="%s" alt="%s" title="%s"' % (src, text, title)
        else:
            html = '<img src="%s" alt="%s"' % (src, text)
        if self.options.get('use_xhtml'):
            return '%s />' % html
        return '%s>' % html

    def inline_html(self, html):
        """Rendering span level pure html content.

        :param html: text content of the html snippet.
        """
        if self.options.get('escape'):
            return escape(html)
        return html

    def newline(self):
        """Rendering newline element."""
        return ''

    def footnote_ref(self, key, index):
        """Rendering the ref anchor of a footnote.

        :param key: identity key for the footnote.
        :param index: the index count of current footnote.
        """
        html = (
            '<sup class="footnote-ref" id="fnref-%s">'
            '<a href="#fn-%s" rel="footnote">%d</a></sup>'
        ) % (escape(key), escape(key), index)
        return html

    def footnote_item(self, key, text):
        """Rendering a footnote item.

        :param key: identity key for the footnote.
        :param text: text content of the footnote.
        """
        back = (
            '<a href="#fnref-%s" rev="footnote">&#8617;</a>'
        ) % escape(key)
        text = text.rstrip()
        if text.endswith('</p>'):
            text = re.sub(r'<\/p>$', r'%s</p>' % back, text)
        else:
            text = '%s<p>%s</p>' % (text, back)
        html = '<li id="fn-%s">%s</li>\n' % (escape(key), text)
        return html

    def footnotes(self, text):
        """Wrapper for all footnotes.

        :param text: contents of all footnotes.
        """
        html = '<div class="footnotes">\n%s<ol>%s</ol>\n</div>\n'
        return html % (self.hrule(), text)


class Markdown(object):
    """The Markdown parser.

    :param renderer: An instance of ``Renderer``.
    :param inline: An inline lexer class or instance.
    :param block: A block lexer class or instance.
    """
    def __init__(self, renderer=None, inline=None, block=None, **kwargs):
        if not renderer:
            renderer = Renderer(**kwargs)
        else:
            kwargs.update(renderer.options)

        self.renderer = renderer

        if inline and inspect.isclass(inline):
            inline = inline(renderer, **kwargs)
        if block and inspect.isclass(block):
            block = block(**kwargs)

        if inline:
            self.inline = inline
        else:
            self.inline = InlineLexer(renderer, **kwargs)

        self.block = block or BlockLexer(BlockGrammar())
        self.footnotes = []
        self.tokens = []

        # detect if it should parse text in block html
        self._parse_block_html = kwargs.get('parse_block_html')

    def __call__(self, text):
        return self.parse(text)

    def render(self, text):
        """Render the Markdown text.

        :param text: markdown formatted text content.
        """
        return self.parse(text)

    def parse(self, text):
        out = self.output(preprocessing(text))

        keys = self.block.def_footnotes

        # reset block
        self.block.def_links = {}
        self.block.def_footnotes = {}

        # reset inline
        self.inline.links = {}
        self.inline.footnotes = {}

        if not self.footnotes:
            return out

        footnotes = filter(lambda o: keys.get(o['key']), self.footnotes)
        self.footnotes = sorted(
            footnotes, key=lambda o: keys.get(o['key']), reverse=True
        )

        body = self.renderer.placeholder()
        while self.footnotes:
            note = self.footnotes.pop()
            body += self.renderer.footnote_item(
                note['key'], note['text']
            )

        out += self.renderer.footnotes(body)
        return out

    def pop(self):
        if not self.tokens:
            return None
        self.token = self.tokens.pop()
        return self.token

    def peek(self):
        if self.tokens:
            return self.tokens[-1]
        return None  # pragma: no cover

    def output(self, text, rules=None):
        self.tokens = self.block(text, rules)
        self.tokens.reverse()

        self.inline.setup(self.block.def_links, self.block.def_footnotes)

        out = self.renderer.placeholder()
        while self.pop():
            out += self.tok()
        return out

    def tok(self):
        t = self.token['type']

        # sepcial cases
        if t.endswith('_start'):
            t = t[:-6]

        return getattr(self, 'output_%s' % t)()

    def tok_text(self):
        text = self.token['text']
        while self.peek()['type'] == 'text':
            text += '\n' + self.pop()['text']
        return self.inline(text)

    def output_newline(self):
        return self.renderer.newline()

    def output_hrule(self):
        return self.renderer.hrule()

    def output_heading(self):
        return self.renderer.header(
            self.inline(self.token['text']),
            self.token['level'],
            self.token['text'],
        )

    def output_code(self):
        return self.renderer.block_code(
            self.token['text'], self.token['lang']
        )

    def output_table(self):
        aligns = self.token['align']
        aligns_length = len(aligns)
        cell = self.renderer.placeholder()

        # header part
        header = self.renderer.placeholder()
        for i, value in enumerate(self.token['header']):
            align = aligns[i] if i < aligns_length else None
            flags = {'header': True, 'align': align}
            cell += self.renderer.table_cell(self.inline(value), **flags)

        header += self.renderer.table_row(cell)

        # body part
        body = self.renderer.placeholder()
        for i, row in enumerate(self.token['cells']):
            cell = self.renderer.placeholder()
            for j, value in enumerate(row):
                align = aligns[j] if j < aligns_length else None
                flags = {'header': False, 'align': align}
                cell += self.renderer.table_cell(self.inline(value), **flags)
            body += self.renderer.table_row(cell)

        return self.renderer.table(header, body)

    def output_block_quote(self):
        body = self.renderer.placeholder()
        while self.pop()['type'] != 'block_quote_end':
            body += self.tok()
        return self.renderer.block_quote(body)

    def output_list(self):
        ordered = self.token['ordered']
        body = self.renderer.placeholder()
        while self.pop()['type'] != 'list_end':
            body += self.tok()
        return self.renderer.list(body, ordered)

    def output_list_item(self):
        body = self.renderer.placeholder()
        while self.pop()['type'] != 'list_item_end':
            if self.token['type'] == 'text':
                body += self.tok_text()
            else:
                body += self.tok()

        return self.renderer.list_item(body)

    def output_loose_item(self):
        body = self.renderer.placeholder()
        while self.pop()['type'] != 'list_item_end':
            body += self.tok()
        return self.renderer.list_item(body)

    def output_footnote(self):
        self.inline._in_footnote = True
        body = self.renderer.placeholder()
        key = self.token['key']
        while self.pop()['type'] != 'footnote_end':
            body += self.tok()
        self.footnotes.append({'key': key, 'text': body})
        self.inline._in_footnote = False
        return self.renderer.placeholder()

    def output_close_html(self):
        text = self.token['text']
        return self.renderer.block_html(text)

    def output_open_html(self):
        text = self.token['text']
        tag = self.token['tag']
        if self._parse_block_html and tag not in _pre_tags:
            text = self.inline(text, rules=self.inline.inline_html_rules)
        extra = self.token.get('extra') or ''
        html = '<%s%s>%s</%s>' % (tag, extra, text, tag)
        return self.renderer.block_html(html)

    def output_paragraph(self):
        return self.renderer.paragraph(self.inline(self.token['text']))

    def output_text(self):
        return self.renderer.paragraph(self.tok_text())


def markdown(text, escape=True, **kwargs):
    """Render markdown formatted text to html.

    :param text: markdown formatted text content.
    :param escape: if set to False, all html tags will not be escaped.
    :param use_xhtml: output with xhtml tags.
    :param hard_wrap: if set to True, it will use the GFM line breaks feature.
    :param parse_block_html: parse text only in block level html.
    :param parse_inline_html: parse text only in inline level html.
    """
    return Markdown(escape=escape, **kwargs)(text)