import markdown
import re
def isString(s):
""" Check if it's string """
return isinstance(s, unicode) or isinstance(s, str)
class Processor:
def __init__(self, markdown_instance=None):
if markdown_instance:
self.markdown = markdown_instance
class Treeprocessor(Processor):
"""
Treeprocessors are run on the ElementTree object before serialization.
Each Treeprocessor implements a "run" method that takes a pointer to an
ElementTree, modifies it as necessary and returns an ElementTree
object.
Treeprocessors must extend markdown.Treeprocessor.
"""
def run(self, root):
"""
Subclasses of Treeprocessor should implement a `run` method, which
takes a root ElementTree. This method can return another ElementTree
object, and the existing root ElementTree will be replaced, or it can
modify the current tree and return None.
"""
pass
class InlineProcessor(Treeprocessor):
"""
A Treeprocessor that traverses a tree, applying inline patterns.
"""
def __init__ (self, md):
self.__placeholder_prefix = markdown.INLINE_PLACEHOLDER_PREFIX
self.__placeholder_suffix = markdown.ETX
self.__placeholder_length = 4 + len(self.__placeholder_prefix) \
+ len(self.__placeholder_suffix)
self.__placeholder_re = re.compile(markdown.INLINE_PLACEHOLDER % r'([0-9]{4})')
self.markdown = md
def __makePlaceholder(self, type):
""" Generate a placeholder """
id = "%04d" % len(self.stashed_nodes)
hash = markdown.INLINE_PLACEHOLDER % id
return hash, id
def __findPlaceholder(self, data, index):
"""
Extract id from data string, start from index
Keyword arguments:
* data: string
* index: index, from which we start search
Returns: placeholder id and string index, after the found placeholder.
"""
m = self.__placeholder_re.search(data, index)
if m:
return m.group(1), m.end()
else:
return None, index + 1
def __stashNode(self, node, type):
""" Add node to stash """
placeholder, id = self.__makePlaceholder(type)
self.stashed_nodes[id] = node
return placeholder
def __handleInline(self, data, patternIndex=0):
"""
Process string with inline patterns and replace it
with placeholders
Keyword arguments:
* data: A line of Markdown text
* patternIndex: The index of the inlinePattern to start with
Returns: String with placeholders.
"""
if not isinstance(data, markdown.AtomicString):
startIndex = 0
while patternIndex < len(self.markdown.inlinePatterns):
data, matched, startIndex = self.__applyPattern(
self.markdown.inlinePatterns.value_for_index(patternIndex),
data, patternIndex, startIndex)
if not matched:
patternIndex += 1
return data
def __processElementText(self, node, subnode, isText=True):
"""
Process placeholders in Element.text or Element.tail
of Elements popped from self.stashed_nodes.
Keywords arguments:
* node: parent node
* subnode: processing node
* isText: bool variable, True - it's text, False - it's tail
Returns: None
"""
if isText:
text = subnode.text
subnode.text = None
else:
text = subnode.tail
subnode.tail = None
childResult = self.__processPlaceholders(text, subnode)
if not isText and node is not subnode:
pos = node.getchildren().index(subnode)
node.remove(subnode)
else:
pos = 0
childResult.reverse()
for newChild in childResult:
node.insert(pos, newChild)
def __processPlaceholders(self, data, parent):
"""
Process string with placeholders and generate ElementTree tree.
Keyword arguments:
* data: string with placeholders instead of ElementTree elements.
* parent: Element, which contains processing inline data
Returns: list with ElementTree elements with applied inline patterns.
"""
def linkText(text):
if text:
if result:
if result[-1].tail:
result[-1].tail += text
else:
result[-1].tail = text
else:
if parent.text:
parent.text += text
else:
parent.text = text
result = []
strartIndex = 0
while data:
index = data.find(self.__placeholder_prefix, strartIndex)
if index != -1:
id, phEndIndex = self.__findPlaceholder(data, index)
if id in self.stashed_nodes:
node = self.stashed_nodes.get(id)
if index > 0:
text = data[strartIndex:index]
linkText(text)
if not isString(node): # it's Element
for child in [node] + node.getchildren():
if child.tail:
if child.tail.strip():
self.__processElementText(node, child, False)
if child.text:
if child.text.strip():
self.__processElementText(child, child)
else: # it's just a string
linkText(node)
strartIndex = phEndIndex
continue
strartIndex = phEndIndex
result.append(node)
else: # wrong placeholder
end = index + len(prefix)
linkText(data[strartIndex:end])
strartIndex = end
else:
text = data[strartIndex:]
linkText(text)
data = ""
return result
def __applyPattern(self, pattern, data, patternIndex, startIndex=0):
"""
Check if the line fits the pattern, create the necessary
elements, add it to stashed_nodes.
Keyword arguments:
* data: the text to be processed
* pattern: the pattern to be checked
* patternIndex: index of current pattern
* startIndex: string index, from which we starting search
Returns: String with placeholders instead of ElementTree elements.
"""
match = pattern.getCompiledRegExp().match(data[startIndex:])
leftData = data[:startIndex]
if not match:
return data, False, 0
node = pattern.handleMatch(match)
if node is None:
return data, True, len(leftData) + match.span(len(match.groups()))[0]
if not isString(node):
if not isinstance(node.text, markdown.AtomicString):
# We need to process current node too
for child in [node] + node.getchildren():
if not isString(node):
if child.text:
child.text = self.__handleInline(child.text,
patternIndex + 1)
if child.tail:
child.tail = self.__handleInline(child.tail,
patternIndex)
placeholder = self.__stashNode(node, pattern.type())
return "%s%s%s%s" % (leftData,
match.group(1),
placeholder, match.groups()[-1]), True, 0
def run(self, tree):
"""Apply inline patterns to a parsed Markdown tree.
Iterate over ElementTree, find elements with inline tag, apply inline
patterns and append newly created Elements to tree. If you don't
want process your data with inline paterns, instead of normal string,
use subclass AtomicString:
node.text = markdown.AtomicString("data won't be processed with inline patterns")
Arguments:
* markdownTree: ElementTree object, representing Markdown tree.
Returns: ElementTree object with applied inline patterns.
"""
self.stashed_nodes = {}
stack = [tree]
while stack:
currElement = stack.pop()
insertQueue = []
for child in currElement.getchildren():
if child.text and not isinstance(child.text, markdown.AtomicString):
text = child.text
child.text = None
lst = self.__processPlaceholders(self.__handleInline(
text), child)
stack += lst
insertQueue.append((child, lst))
if child.getchildren():
stack.append(child)
for element, lst in insertQueue:
if element.text:
element.text = \
markdown.inlinepatterns.handleAttributes(element.text,
element)
i = 0
for newChild in lst:
# Processing attributes
if newChild.tail:
newChild.tail = \
markdown.inlinepatterns.handleAttributes(newChild.tail,
element)
if newChild.text:
newChild.text = \
markdown.inlinepatterns.handleAttributes(newChild.text,
newChild)
element.insert(i, newChild)
i += 1
return tree
class PrettifyTreeprocessor(Treeprocessor):
""" Add linebreaks to the html document. """
def _prettifyETree(self, elem):
""" Recursively add linebreaks to ElementTree children. """
i = "\n"
if markdown.isBlockLevel(elem.tag) and elem.tag not in ['code', 'pre']:
if (not elem.text or not elem.text.strip()) \
and len(elem) and markdown.isBlockLevel(elem[0].tag):
elem.text = i
for e in elem:
if markdown.isBlockLevel(e.tag):
self._prettifyETree(e)
if not elem.tail or not elem.tail.strip():
elem.tail = i
if not elem.tail or not elem.tail.strip():
elem.tail = i
def run(self, root):
""" Add linebreaks to ElementTree root object. """
self._prettifyETree(root)
# Do <br />'s seperately as they are often in the middle of
# inline content and missed by _prettifyETree.
brs = root.getiterator('br')
for br in brs:
if not br.tail or not br.tail.strip():
br.tail = '\n'
else:
br.tail = '\n%s' % br.tail