"""
Legacy Extension for Python-Markdown
====================================
Replaces the core parser with the old one.
"""
import markdown
"""Basic and reusable regular expressions."""
def wrapRe(raw_re) : return re.compile("^%s$" % raw_re, re.DOTALL)
CORE_RE = {
'header': wrapRe(r'(#{1,6})[ \t]*(.*?)[ \t]*(#*)'), # # A title
'reference-def': wrapRe(r'(\ ?\ ?\ ?)\[([^\]]*)\]:\s*([^ ]*)(.*)'),
# [Google]: http://www.google.com/
'containsline': wrapRe(r'([-]*)$|^([=]*)'), # -----, =====, etc.
'ol': wrapRe(r'[ ]{0,3}[\d]*\.\s+(.*)'), # 1. text
'ul': wrapRe(r'[ ]{0,3}[*+-]\s+(.*)'), # "* text"
'isline1': wrapRe(r'(\**)'), # ***
'isline2': wrapRe(r'(\-*)'), # ---
'isline3': wrapRe(r'(\_*)'), # ___
'tabbed': wrapRe(r'((\t)|( ))(.*)'), # an indented line
'quoted': wrapRe(r'[ ]{0,2}> ?(.*)'), # a quoted block ("> ...")
'containsline': re.compile(r'^([-]*)$|^([=]*)$', re.M),
'attr': re.compile("\{@([^\}]*)=([^\}]*)}") # {@id=123}
}
class MarkdownParser:
"""Parser Markdown into a ElementTree."""
def __init__(self):
pass
def parseDocument(self, lines):
"""Parse a markdown string into an ElementTree."""
# Create a ElementTree from the lines
root = etree.Element("div")
buffer = []
for line in lines:
if line.startswith("#"):
self.parseChunk(root, buffer)
buffer = [line]
else:
buffer.append(line)
self.parseChunk(root, buffer)
return etree.ElementTree(root)
def parseChunk(self, parent_elem, lines, inList=0, looseList=0):
"""Process a chunk of markdown-formatted text and attach the parse to
an ElementTree node.
Process a section of a source document, looking for high
level structural elements like lists, block quotes, code
segments, html blocks, etc. Some those then get stripped
of their high level markup (e.g. get unindented) and the
lower-level markup is processed recursively.
Keyword arguments:
* parent_elem: The ElementTree element to which the content will be
added.
* lines: a list of lines
* inList: a level
Returns: None
"""
# Loop through lines until none left.
while lines:
# Skipping empty line
if not lines[0]:
lines = lines[1:]
continue
# Check if this section starts with a list, a blockquote or
# a code block. If so, process them.
processFn = { 'ul': self.__processUList,
'ol': self.__processOList,
'quoted': self.__processQuote,
'tabbed': self.__processCodeBlock}
for regexp in ['ul', 'ol', 'quoted', 'tabbed']:
m = CORE_RE[regexp].match(lines[0])
if m:
processFn[regexp](parent_elem, lines, inList)
return
# We are NOT looking at one of the high-level structures like
# lists or blockquotes. So, it's just a regular paragraph
# (though perhaps nested inside a list or something else). If
# we are NOT inside a list, we just need to look for a blank
# line to find the end of the block. If we ARE inside a
# list, however, we need to consider that a sublist does not
# need to be separated by a blank line. Rather, the following
# markup is legal:
#
# * The top level list item
#
# Another paragraph of the list. This is where we are now.
# * Underneath we might have a sublist.
#
if inList:
start, lines = self.__linesUntil(lines, (lambda line:
CORE_RE['ul'].match(line)
or CORE_RE['ol'].match(line)
or not line.strip()))
self.parseChunk(parent_elem, start, inList-1,
looseList=looseList)
inList = inList-1
else: # Ok, so it's just a simple block
test = lambda line: not line.strip() or line[0] == '>'
paragraph, lines = self.__linesUntil(lines, test)
if len(paragraph) and paragraph[0].startswith('#'):
self.__processHeader(parent_elem, paragraph)
elif len(paragraph) and CORE_RE["isline3"].match(paragraph[0]):
self.__processHR(parent_elem)
lines = paragraph[1:] + lines
elif paragraph:
self.__processParagraph(parent_elem, paragraph,
inList, looseList)
if lines and not lines[0].strip():
lines = lines[1:] # skip the first (blank) line
def __processHR(self, parentElem):
hr = etree.SubElement(parentElem, "hr")
def __processHeader(self, parentElem, paragraph):
m = CORE_RE['header'].match(paragraph[0])
if m:
level = len(m.group(1))
h = etree.SubElement(parentElem, "h%d" % level)
h.text = m.group(2).strip()
else:
message(CRITICAL, "We've got a problem header!")
def __processParagraph(self, parentElem, paragraph, inList, looseList):
if ( parentElem.tag == 'li'
and not (looseList or parentElem.getchildren())):
# If this is the first paragraph inside "li", don't
# put around it - append the paragraph bits directly
# onto parentElem
el = parentElem
else:
# Otherwise make a "p" element
el = etree.SubElement(parentElem, "p")
dump = []
# Searching for hr or header
for line in paragraph:
# it's hr
if CORE_RE["isline3"].match(line):
el.text = "\n".join(dump)
self.__processHR(el)
dump = []
# it's header
elif line.startswith("#"):
el.text = "\n".join(dump)
self.__processHeader(parentElem, [line])
dump = []
else:
dump.append(line)
if dump:
text = "\n".join(dump)
el.text = text
def __processUList(self, parentElem, lines, inList):
self.__processList(parentElem, lines, inList, listexpr='ul', tag='ul')
def __processOList(self, parentElem, lines, inList):
self.__processList(parentElem, lines, inList, listexpr='ol', tag='ol')
def __processList(self, parentElem, lines, inList, listexpr, tag):
"""
Given a list of document lines starting with a list item,
finds the end of the list, breaks it up, and recursively
processes each list item and the remainder of the text file.
Keyword arguments:
* parentElem: A ElementTree element to which the content will be added
* lines: a list of lines
* inList: a level
Returns: None
"""
ul = etree.SubElement(parentElem, tag) # ul might actually be '
'
looseList = 0
# Make a list of list items
items = []
item = -1
i = 0 # a counter to keep track of where we are
for line in lines:
loose = 0
if not line.strip():
# If we see a blank line, this _might_ be the end of the list
i += 1
loose = 1
# Find the next non-blank line
for j in range(i, len(lines)):
if lines[j].strip():
next = lines[j]
break
else:
# There is no more text => end of the list
break
# Check if the next non-blank line is still a part of the list
if ( CORE_RE[listexpr].match(next) or
CORE_RE['tabbed'].match(next) ):
# get rid of any white space in the line
items[item].append(line.strip())
looseList = loose or looseList
continue
else:
break # found end of the list
# Now we need to detect list items (at the current level)
# while also detabing child elements if necessary
for expr in ['ul', 'ol', 'tabbed']:
m = CORE_RE[expr].match(line)
if m:
if expr in ['ul', 'ol']: # We are looking at a new item
#if m.group(1) :
# Removed the check to allow for a blank line
# at the beginning of the list item
items.append([m.group(1)])
item += 1
elif expr == 'tabbed': # This line needs to be detabbed
items[item].append(m.group(4)) #after the 'tab'
i += 1
break
else:
items[item].append(line) # Just regular continuation
i += 1 # added on 2006.02.25
else:
i += 1
# Add the ElementTree elements
for item in items:
li = etree.SubElement(ul, "li")
self.parseChunk(li, item, inList + 1, looseList = looseList)
# Process the remaining part of the section
self.parseChunk(parentElem, lines[i:], inList)
def __linesUntil(self, lines, condition):
"""
A utility function to break a list of lines upon the
first line that satisfied a condition. The condition
argument should be a predicate function.
"""
i = -1
for line in lines:
i += 1
if condition(line):
break
else:
i += 1
return lines[:i], lines[i:]
def __processQuote(self, parentElem, lines, inList):
"""
Given a list of document lines starting with a quote finds
the end of the quote, unindents it and recursively
processes the body of the quote and the remainder of the
text file.
Keyword arguments:
* parentElem: ElementTree element to which the content will be added
* lines: a list of lines
* inList: a level
Returns: None
"""
dequoted = []
i = 0
blank_line = False # allow one blank line between paragraphs
for line in lines:
m = CORE_RE['quoted'].match(line)
if m:
dequoted.append(m.group(1))
i += 1
blank_line = False
elif not blank_line and line.strip() != '':
dequoted.append(line)
i += 1
elif not blank_line and line.strip() == '':
dequoted.append(line)
i += 1
blank_line = True
else:
break
blockquote = etree.SubElement(parentElem, "blockquote")
self.parseChunk(blockquote, dequoted, inList)
self.parseChunk(parentElem, lines[i:], inList)
def __processCodeBlock(self, parentElem, lines, inList):
"""
Given a list of document lines starting with a code block
finds the end of the block, puts it into the ElementTree verbatim
wrapped in ("") and recursively processes the
the remainder of the text file.
Keyword arguments:
* parentElem: ElementTree element to which the content will be added
* lines: a list of lines
* inList: a level
Returns: None
"""
detabbed, theRest = self.detectTabbed(lines)
pre = etree.SubElement(parentElem, "pre")
code = etree.SubElement(pre, "code")
text = "\n".join(detabbed).rstrip()+"\n"
code.text = AtomicString(text)
self.parseChunk(parentElem, theRest, inList)
def detectTabbed(self, lines):
""" Find indented text and remove indent before further proccesing.
Keyword arguments:
* lines: an array of strings
* fn: a function that returns a substring of a string
if the string matches the necessary criteria
Returns: a list of post processes items and the unused
remainder of the original list
"""
items = []
item = -1
i = 0 # to keep track of where we are
def detab(line):
match = CORE_RE['tabbed'].match(line)
if match:
return match.group(4)
for line in lines:
if line.strip(): # Non-blank line
line = detab(line)
if line:
items.append(line)
i += 1
continue
else:
return items, lines[i:]
else: # Blank line: _maybe_ we are done.
i += 1 # advance
# Find the next non-blank line
for j in range(i, len(lines)):
if lines[j].strip():
next_line = lines[j]; break
else:
break # There is no more text; we are done.
# Check if the next non-blank line is tabbed
if detab(next_line): # Yes, more work to do.
items.append("")
continue
else:
break # No, we are done.
else:
i += 1
return items, lines[i:]
class HeaderPreprocessor(Preprocessor):
"""Replace underlined headers with hashed headers.
(To avoid the need for lookahead later.)
"""
def run (self, lines):
i = -1
while i+1 < len(lines):
i = i+1
if not lines[i].strip():
continue
if lines[i].startswith("#"):
lines.insert(i+1, "\n")
if (i+1 <= len(lines)
and lines[i+1]
and lines[i+1][0] in ['-', '=']):
underline = lines[i+1].strip()
if underline == "="*len(underline):
lines[i] = "# " + lines[i].strip()
lines[i+1] = ""
elif underline == "-"*len(underline):
lines[i] = "## " + lines[i].strip()
lines[i+1] = ""
return lines
class LinePreprocessor(Preprocessor):
"""Convert HR lines to "___" format."""
blockquote_re = re.compile(r'^(> )+')
def run (self, lines):
for i in range(len(lines)):
prefix = ''
m = self.blockquote_re.search(lines[i])
if m:
prefix = m.group(0)
if self._isLine(lines[i][len(prefix):]):
lines[i] = prefix + "___"
return lines
def _isLine(self, block):
"""Determine if a block should be replaced with an
"""
if block.startswith(" "):
return False # a code block
text = "".join([x for x in block if not x.isspace()])
if len(text) <= 2:
return False
for pattern in ['isline1', 'isline2', 'isline3']:
m = CORE_RE[pattern].match(text)
if (m and m.group(1)):
return True
else:
return False
class LegacyExtension(markdown.Extension):
""" Replace Markdown's core parser. """
def extendMarkdown(self, md, md_globals):
""" Set the core parser to an instance of MarkdownParser. """
md.parser = MarkdownParser()
md.preprocessors.add ("header", HeaderPreprocessor(self), "