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"""
========================= FOOTNOTES =================================
This section adds footnote handling to markdown. It can be used as
an example for extending python-markdown with relatively complex
functionality. While in this case the extension is included inside
the module itself, it could just as easily be added from outside the
module. Not that all markdown classes above are ignorant about
footnotes. All footnote functionality is provided separately and
then added to the markdown instance at the run time.
Footnote functionality is attached by calling extendMarkdown()
method of FootnoteExtension. The method also registers the
extension to allow it's state to be reset by a call to reset()
method.
"""
FN_BACKLINK_TEXT = "zz1337820767766393qq"
import re, markdown, random
class FootnoteExtension (markdown.Extension):
DEF_RE = re.compile(r'(\ ?\ ?\ ?)\[\^([^\]]*)\]:\s*(.*)')
SHORT_USE_RE = re.compile(r'\[\^([^\]]*)\]', re.M) # [^a]
def __init__ (self, configs) :
self.config = {'PLACE_MARKER' :
["///Footnotes Go Here///",
"The text string that marks where the footnotes go"]}
for key, value in configs :
self.config[key][0] = value
self.reset()
def extendMarkdown(self, md, md_globals) :
self.md = md
# Stateless extensions do not need to be registered
md.registerExtension(self)
# Insert a preprocessor before ReferencePreprocessor
index = md.preprocessors.index(md_globals['REFERENCE_PREPROCESSOR'])
preprocessor = FootnotePreprocessor(self)
preprocessor.md = md
md.preprocessors.insert(index, preprocessor)
# Insert an inline pattern before ImageReferencePattern
FOOTNOTE_RE = r'\[\^([^\]]*)\]' # blah blah [^1] blah
index = md.inlinePatterns.index(md_globals['IMAGE_REFERENCE_PATTERN'])
md.inlinePatterns.insert(index, FootnotePattern(FOOTNOTE_RE, self))
# Insert a post-processor that would actually add the footnote div
postprocessor = FootnotePostprocessor(self)
postprocessor.extension = self
md.postprocessors.append(postprocessor)
textPostprocessor = FootnoteTextPostprocessor(self)
md.textPostprocessors.append(textPostprocessor)
def reset(self) :
# May be called by Markdown is state reset is desired
self.footnote_suffix = "-" + str(int(random.random()*1000000000))
self.used_footnotes={}
self.footnotes = {}
def findFootnotesPlaceholder(self, doc) :
def findFootnotePlaceholderFn(node=None, indent=0):
if node.type == 'text':
if node.value.find(self.getConfig("PLACE_MARKER")) > -1 :
return True
fn_div_list = doc.find(findFootnotePlaceholderFn)
if fn_div_list :
return fn_div_list[0]
def setFootnote(self, id, text) :
self.footnotes[id] = text
def makeFootnoteId(self, num) :
return 'fn%d%s' % (num, self.footnote_suffix)
def makeFootnoteRefId(self, num) :
return 'fnr%d%s' % (num, self.footnote_suffix)
def makeFootnotesDiv (self, doc) :
"""Creates the div with class='footnote' and populates it with
the text of the footnotes.
@returns: the footnote div as a dom element """
if not self.footnotes.keys() :
return None
div = doc.createElement("div")
div.setAttribute('class', 'footnote')
hr = doc.createElement("hr")
div.appendChild(hr)
ol = doc.createElement("ol")
div.appendChild(ol)
footnotes = [(self.used_footnotes[id], id)
for id in self.footnotes.keys()]
footnotes.sort()
for i, id in footnotes :
li = doc.createElement('li')
li.setAttribute('id', self.makeFootnoteId(i))
self.md._processSection(li, self.footnotes[id].split("\n"), looseList=1)
#li.appendChild(doc.createTextNode(self.footnotes[id]))
backlink = doc.createElement('a')
backlink.setAttribute('href', '#' + self.makeFootnoteRefId(i))
backlink.setAttribute('class', 'footnoteBackLink')
backlink.setAttribute('title',
'Jump back to footnote %d in the text' % 1)
backlink.appendChild(doc.createTextNode(FN_BACKLINK_TEXT))
if li.childNodes :
node = li.childNodes[-1]
if node.type == "text" :
li.appendChild(backlink)
elif node.nodeName == "p":
node.appendChild(backlink)
else:
p = doc.createElement('p')
p.appendChild(backlink)
li.appendChild(p)
ol.appendChild(li)
return div
class FootnotePreprocessor :
def __init__ (self, footnotes) :
self.footnotes = footnotes
def run(self, lines) :
self.blockGuru = markdown.BlockGuru()
lines = self._handleFootnoteDefinitions (lines)
# Make a hash of all footnote marks in the text so that we
# know in what order they are supposed to appear. (This
# function call doesn't really substitute anything - it's just
# a way to get a callback for each occurence.
text = "\n".join(lines)
self.footnotes.SHORT_USE_RE.sub(self.recordFootnoteUse, text)
return text.split("\n")
def recordFootnoteUse(self, match) :
id = match.group(1)
id = id.strip()
nextNum = len(self.footnotes.used_footnotes.keys()) + 1
self.footnotes.used_footnotes[id] = nextNum
def _handleFootnoteDefinitions(self, lines) :
"""Recursively finds all footnote definitions in the lines.
@param lines: a list of lines of text
@returns: a string representing the text with footnote
definitions removed """
i, id, footnote = self._findFootnoteDefinition(lines)
if id :
plain = lines[:i]
detabbed, theRest = self.blockGuru.detectTabbed(lines[i+1:])
self.footnotes.setFootnote(id,
footnote + "\n"
+ "\n".join(detabbed))
more_plain = self._handleFootnoteDefinitions(theRest)
return plain + [""] + more_plain
else :
return lines
def _findFootnoteDefinition(self, lines) :
"""Finds the first line of a footnote definition.
@param lines: a list of lines of text
@returns: the index of the line containing a footnote definition """
counter = 0
for line in lines :
m = self.footnotes.DEF_RE.match(line)
if m :
return counter, m.group(2), m.group(3)
counter += 1
return counter, None, None
class FootnotePattern (markdown.Pattern) :
def __init__ (self, pattern, footnotes) :
markdown.Pattern.__init__(self, pattern)
self.footnotes = footnotes
def handleMatch(self, m, doc) :
sup = doc.createElement('sup')
a = doc.createElement('a')
sup.appendChild(a)
id = m.group(2)
num = self.footnotes.used_footnotes[id]
sup.setAttribute('id', self.footnotes.makeFootnoteRefId(num))
a.setAttribute('href', '#' + self.footnotes.makeFootnoteId(num))
a.appendChild(doc.createTextNode(str(num)))
return sup
class FootnotePostprocessor (markdown.Postprocessor):
def __init__ (self, footnotes) :
self.footnotes = footnotes
def run(self, doc) :
footnotesDiv = self.footnotes.makeFootnotesDiv(doc)
if footnotesDiv :
fnPlaceholder = self.extension.findFootnotesPlaceholder(doc)
if fnPlaceholder :
fnPlaceholder.parent.replaceChild(fnPlaceholder, footnotesDiv)
else :
doc.documentElement.appendChild(footnotesDiv)
class FootnoteTextPostprocessor (markdown.Postprocessor):
def __init__ (self, footnotes) :
self.footnotes = footnotes
def run(self, text) :
return text.replace(FN_BACKLINK_TEXT, "↩")
def makeExtension(configs=None) :
return FootnoteExtension(configs=configs)
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