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| -rw-r--r-- | mdx_footnotes.py | 252 |
1 files changed, 252 insertions, 0 deletions
diff --git a/mdx_footnotes.py b/mdx_footnotes.py new file mode 100644 index 0000000..56ffd3a --- /dev/null +++ b/mdx_footnotes.py @@ -0,0 +1,252 @@ +""" +========================= 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")) + + #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" : + node = li + node.appendChild(backlink) + + 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) + |