renamed extension module and set import to extension module first, then mdx_filename

1 files changed, 276 insertions, 0 deletions

diff --git a/markdown_extensions/footnotes.py b/markdown_extensions/footnotes.py
new file mode 100644
index 0000000..b46efbb
--- /dev/null
+++ b/markdown_extensions/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)
+