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Diffstat (limited to 'mdx/mdx_footnotes.py')
| -rw-r--r-- | mdx/mdx_footnotes.py | 276 |
1 files changed, 276 insertions, 0 deletions
diff --git a/mdx/mdx_footnotes.py b/mdx/mdx_footnotes.py new file mode 100644 index 0000000..b46efbb --- /dev/null +++ b/mdx/mdx_footnotes.py @@ -0,0 +1,276 @@ +""" +========================= 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 +from markdown import etree + +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, root): + + def finder(element): + for child in element: + if child.text: + if child.text.find(self.getConfig("PLACE_MARKER")) > -1: + return child, True + if child.tail: + if child.tail.find(self.getConfig("PLACE_MARKER")) > -1: + return (child, element), False + finder(child) + return None + + res = finder(root) + return res + + + 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, root) : + """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 = etree.Element("div") + div.set('class', 'footnote') + hr = etree.SubElement(div, "hr") + ol = etree.SubElement(div, "ol") + + + footnotes = [(self.used_footnotes[id], id) + for id in self.footnotes.keys()] + footnotes.sort() + + for i, id in footnotes : + li = etree.SubElement(ol, "li") + li.set("id", self.makeFootnoteId(i)) + + self.md._processSection(li, self.footnotes[id].split("\n"), looseList=1) + + backlink = etree.Element("a") + backlink.set("href", "#" + self.makeFootnoteRefId(i)) + backlink.set("class", "footnoteBackLink") + backlink.set("title", + "Jump back to footnote %d in the text" % i) + backlink.text = FN_BACKLINK_TEXT + + if li.getchildren(): + node = li[-1] + if node.text: + li.append(backlink) + elif node.tag == "p": + node.append(backlink) + else: + p = etree.SubElement(li, "p") + p.append(backlink) + div = self.md.applyInlinePatterns(etree.ElementTree(div)).getroot() + 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) : + sup = etree.Element("sup") + a = etree.SubElement(sup, "a") + id = m.group(2) + num = self.footnotes.used_footnotes[id] + sup.set('id', self.footnotes.makeFootnoteRefId(num)) + a.set('href', '#' + self.footnotes.makeFootnoteId(num)) + a.text = str(num) + return sup + +class FootnotePostprocessor (markdown.Postprocessor): + + def __init__ (self, footnotes) : + self.footnotes = footnotes + + def run(self, root): + footnotesDiv = self.footnotes.makeFootnotesDiv(root) + if footnotesDiv: + result = self.extension.findFootnotesPlaceholder(root) + + if result: + node, isText = result + if isText: + node.text = None + node.getchildren().insert(0, footnotesDiv) + else: + child, element = node + ind = element.getchildren().find(child) + element.getchildren().insert(ind + 1, footnotesDiv) + child.tail = None + + fnPlaceholder.parent.replaceChild(fnPlaceholder, footnotesDiv) + else : + root.append(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) + |