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Table of Contents Extension for Python-Markdown
See <>
for documentation.
Oringinal code Copyright 2008 [Jack Miller](
All changes Copyright 2008-2014 The Python Markdown Project
License: [BSD](
from . import Extension
from ..treeprocessors import Treeprocessor
from ..util import code_escape, parseBoolValue, AMP_SUBSTITUTE, HTML_PLACEHOLDER_RE, AtomicString
from ..treeprocessors import UnescapeTreeprocessor
import re
import html
import unicodedata
import xml.etree.ElementTree as etree
def slugify(value, separator, unicode=False):
""" Slugify a string, to make it URL friendly. """
if not unicode:
# Replace Extended Latin characters with ASCII, i.e. žlutý → zluty
value = unicodedata.normalize('NFKD', value)
value = value.encode('ascii', 'ignore').decode('ascii')
value = re.sub(r'[^\w\s-]', '', value).strip().lower()
return re.sub(r'[{}\s]+'.format(separator), separator, value)
def slugify_unicode(value, separator):
""" Slugify a string, to make it URL friendly while preserving Unicode characters. """
return slugify(value, separator, unicode=True)
IDCOUNT_RE = re.compile(r'^(.*)_([0-9]+)$')
def unique(id, ids):
""" Ensure id is unique in set of ids. Append '_1', '_2'... if not """
while id in ids or not id:
m = IDCOUNT_RE.match(id)
if m:
id = '%s_%d' % (, int(
id = '%s_%d' % (id, 1)
return id
def get_name(el):
"""Get title name."""
text = []
for c in el.itertext():
if isinstance(c, AtomicString):
return ''.join(text).strip()
def stashedHTML2text(text, md, strip_entities=True):
""" Extract raw HTML from stash, reduce to plain text and swap with placeholder. """
def _html_sub(m):
""" Substitute raw html with plain text. """
raw = md.htmlStash.rawHtmlBlocks[int(]
except (IndexError, TypeError): # pragma: no cover
# Strip out tags and/or entities - leaving text
res = re.sub(r'(<[^>]+>)', '', raw)
if strip_entities:
res = re.sub(r'(&[\#a-zA-Z0-9]+;)', '', res)
return res
return HTML_PLACEHOLDER_RE.sub(_html_sub, text)
def unescape(text):
""" Unescape escaped text. """
c = UnescapeTreeprocessor()
return c.unescape(text)
def nest_toc_tokens(toc_list):
"""Given an unsorted list with errors and skips, return a nested one.
[{'level': 1}, {'level': 2}]
[{'level': 1, 'children': [{'level': 2, 'children': []}]}]
A wrong list is also converted:
[{'level': 2}, {'level': 1}]
[{'level': 2, 'children': []}, {'level': 1, 'children': []}]
ordered_list = []
if len(toc_list):
# Initialize everything by processing the first entry
last = toc_list.pop(0)
last['children'] = []
levels = [last['level']]
parents = []
# Walk the rest nesting the entries properly
while toc_list:
t = toc_list.pop(0)
current_level = t['level']
t['children'] = []
# Reduce depth if current level < last item's level
if current_level < levels[-1]:
# Pop last level since we know we are less than it
# Pop parents and levels we are less than or equal to
to_pop = 0
for p in reversed(parents):
if current_level <= p['level']:
to_pop += 1
else: # pragma: no cover
if to_pop:
levels = levels[:-to_pop]
parents = parents[:-to_pop]
# Note current level as last
# Level is the same, so append to
# the current parent (if available)
if current_level == levels[-1]:
(parents[-1]['children'] if parents
else ordered_list).append(t)
# Current level is > last item's level,
# So make last item a parent and append current as child
last = t
return ordered_list
class TocTreeprocessor(Treeprocessor):
def __init__(self, md, config):
self.marker = config["marker"]
self.title = config["title"]
self.base_level = int(config["baselevel"]) - 1
self.slugify = config["slugify"]
self.sep = config["separator"]
self.toc_class = config["toc_class"]
self.use_anchors = parseBoolValue(config["anchorlink"])
self.anchorlink_class = config["anchorlink_class"]
self.use_permalinks = parseBoolValue(config["permalink"], False)
if self.use_permalinks is None:
self.use_permalinks = config["permalink"]
self.permalink_class = config["permalink_class"]
self.permalink_title = config["permalink_title"]
self.header_rgx = re.compile("[Hh][123456]")
if isinstance(config["toc_depth"], str) and '-' in config["toc_depth"]:
self.toc_top, self.toc_bottom = [int(x) for x in config["toc_depth"].split('-')]
self.toc_top = 1
self.toc_bottom = int(config["toc_depth"])
def iterparent(self, node):
''' Iterator wrapper to get allowed parent and child all at once. '''
# We do not allow the marker inside a header as that
# would causes an enless loop of placing a new TOC
# inside previously generated TOC.
for child in node:
if not self.header_rgx.match(child.tag) and child.tag not in ['pre', 'code']:
yield node, child
yield from self.iterparent(child)
def replace_marker(self, root, elem):
''' Replace marker with elem. '''
for (p, c) in self.iterparent(root):
text = ''.join(c.itertext()).strip()
if not text:
# To keep the output from screwing up the
# validation by putting a <div> inside of a <p>
# we actually replace the <p> in its entirety.
# The <p> element may contain more than a single text content
# (nl2br can introduce a <br>). In this situation, c.text returns
# the very first content, ignore children contents or tail content.
# len(c) == 0 is here to ensure there is only text in the <p>.
if c.text and c.text.strip() == self.marker and len(c) == 0:
for i in range(len(p)):
if p[i] == c:
p[i] = elem
def set_level(self, elem):
''' Adjust header level according to base level. '''
level = int(elem.tag[-1]) + self.base_level
if level > 6:
level = 6
elem.tag = 'h%d' % level
def add_anchor(self, c, elem_id): # @ReservedAssignment
anchor = etree.Element("a")
anchor.text = c.text
anchor.attrib["href"] = "#" + elem_id
anchor.attrib["class"] = self.anchorlink_class
c.text = ""
for elem in c:
while len(c):
def add_permalink(self, c, elem_id):
permalink = etree.Element("a")
permalink.text = ("%spara;" % AMP_SUBSTITUTE
if self.use_permalinks is True
else self.use_permalinks)
permalink.attrib["href"] = "#" + elem_id
permalink.attrib["class"] = self.permalink_class
if self.permalink_title:
permalink.attrib["title"] = self.permalink_title
def build_toc_div(self, toc_list):
""" Return a string div given a toc list. """
div = etree.Element("div")
div.attrib["class"] = self.toc_class
# Add title to the div
if self.title:
header = etree.SubElement(div, "span")
header.attrib["class"] = "toctitle"
header.text = self.title
def build_etree_ul(toc_list, parent):
ul = etree.SubElement(parent, "ul")
for item in toc_list:
# List item link, to be inserted into the toc div
li = etree.SubElement(ul, "li")
link = etree.SubElement(li, "a")
link.text = item.get('name', '')
link.attrib["href"] = '#' + item.get('id', '')
if item['children']:
build_etree_ul(item['children'], li)
return ul
build_etree_ul(toc_list, div)
if 'prettify' in['prettify'].run(div)
return div
def run(self, doc):
# Get a list of id attributes
used_ids = set()
for el in doc.iter():
if "id" in el.attrib:
toc_tokens = []
for el in doc.iter():
if isinstance(el.tag, str) and self.header_rgx.match(el.tag):
text = get_name(el)
# Do not override pre-existing ids
if "id" not in el.attrib:
innertext = unescape(stashedHTML2text(text,
el.attrib["id"] = unique(self.slugify(innertext, self.sep), used_ids)
if int(el.tag[-1]) >= self.toc_top and int(el.tag[-1]) <= self.toc_bottom:
'level': int(el.tag[-1]),
'id': el.attrib["id"],
'name': stashedHTML2text(
code_escape(el.attrib.get('data-toc-label', text)),, strip_entities=False
# Remove the data-toc-label attribute as it is no longer needed
if 'data-toc-label' in el.attrib:
del el.attrib['data-toc-label']
if self.use_anchors:
self.add_anchor(el, el.attrib["id"])
if self.use_permalinks not in [False, None]:
self.add_permalink(el, el.attrib["id"])
toc_tokens = nest_toc_tokens(toc_tokens)
div = self.build_toc_div(toc_tokens)
if self.marker:
self.replace_marker(doc, div)
# serialize and attach to markdown instance.
toc =
for pp in
toc = = toc_tokens = toc
class TocExtension(Extension):
TreeProcessorClass = TocTreeprocessor
def __init__(self, **kwargs):
self.config = {
"marker": ['[TOC]',
'Text to find and replace with Table of Contents - '
'Set to an empty string to disable. Defaults to "[TOC]"'],
"title": ["",
"Title to insert into TOC <div> - "
"Defaults to an empty string"],
"toc_class": ['toc',
'CSS class(es) used for the link. '
'Defaults to "toclink"'],
"anchorlink": [False,
"True if header should be a self link - "
"Defaults to False"],
"anchorlink_class": ['toclink',
'CSS class(es) used for the link. '
'Defaults to "toclink"'],
"permalink": [0,
"True or link text if a Sphinx-style permalink should "
"be added - Defaults to False"],
"permalink_class": ['headerlink',
'CSS class(es) used for the link. '
'Defaults to "headerlink"'],
"permalink_title": ["Permanent link",
"Title attribute of the permalink - "
"Defaults to 'Permanent link'"],
"baselevel": ['1', 'Base level for headers.'],
"slugify": [slugify,
"Function to generate anchors based on header text - "
"Defaults to the headerid ext's slugify function."],
'separator': ['-', 'Word separator. Defaults to "-".'],
"toc_depth": [6,
'Define the range of section levels to include in'
'the Table of Contents. A single integer (b) defines'
'the bottom section level (<h1>..<hb>) only.'
'A string consisting of two digits separated by a hyphen'
'in between ("2-5"), define the top (t) and the'
'bottom (b) (<ht>..<hb>). Defaults to `6` (bottom).'],
def extendMarkdown(self, md):
md.registerExtension(self) = md
tocext = self.TreeProcessorClass(md, self.getConfigs())
# Headerid ext is set to '>prettify'. With this set to '_end',
# it should always come after headerid ext (and honor ids assigned
# by the header id extension) if both are used. Same goes for
# attr_list extension. This must come last because we don't want
# to redefine ids after toc is created. But we do want toc prettified.
md.treeprocessors.register(tocext, 'toc', 5)
def reset(self): = '' = []
def makeExtension(**kwargs): # pragma: no cover
return TocExtension(**kwargs)