""" ========================= 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. Example: Footnotes[^1] have a label[^label] and a definition[^!DEF]. [^1]: This is a footnote [^label]: A footnote on "label" [^!DEF]: The footnote for definition """ 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' % i) 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=[]): return FootnoteExtension(configs=configs)