Check in a simple pure-python based Markdown previewer.

third_party/Python-Markdown/markdown/blockparser.py

-# markdown is released under the BSD license
-# Copyright 2007, 2008 The Python Markdown Project (v. 1.7 and later)
-# Copyright 2004, 2005, 2006 Yuri Takhteyev (v. 0.2-1.6b)
-# Copyright 2004 Manfred Stienstra (the original version)
-# 
-# All rights reserved.
-# 
-# Redistribution and use in source and binary forms, with or without
-# modification, are permitted provided that the following conditions are met:
-# 
-# *   Redistributions of source code must retain the above copyright
-#     notice, this list of conditions and the following disclaimer.
-# *   Redistributions in binary form must reproduce the above copyright
-#     notice, this list of conditions and the following disclaimer in the
-#     documentation and/or other materials provided with the distribution.
-# *   Neither the name of the <organization> nor the
-#     names of its contributors may be used to endorse or promote products
-#     derived from this software without specific prior written permission.
-# 
-# THIS SOFTWARE IS PROVIDED BY THE PYTHON MARKDOWN PROJECT ''AS IS'' AND ANY
-# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
-# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
-# DISCLAIMED. IN NO EVENT SHALL ANY CONTRIBUTORS TO THE PYTHON MARKDOWN PROJECT
-# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
-# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
-# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
-# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
-# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
-# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
-# POSSIBILITY OF SUCH DAMAGE.
-
-
 from __future__ import unicode_literals
 from __future__ import absolute_import
 from . import util
 from . import odict
 
+
 class State(list):
-    """ Track the current and nested state of the parser. 
-    
-    This utility class is used to track the state of the BlockParser and 
+    """ Track the current and nested state of the parser.
+
+    This utility class is used to track the state of the BlockParser and
     support multiple levels if nesting. It's just a simple API wrapped around
     a list. Each time a state is set, that state is appended to the end of the
     list. Each time a state is reset, that state is removed from the end of
     the list.
 
-    Therefore, each time a state is set for a nested block, that state must be 
+    Therefore, each time a state is set for a nested block, that state must be
     reset when we back out of that level of nesting or the state could be
     corrupted.
 
     While all the methods of a list object are available, only the three
     defined below need be used.
 
     """
 
     def set(self, state):
         """ Set a new state. """
         self.append(state)
 
     def reset(self):
         """ Step back one step in nested state. """
         self.pop()
 
     def isstate(self, state):
         """ Test that top (current) level is of given state. """
         if len(self):
             return self[-1] == state
         else:
             return False
 
+
 class BlockParser:
-    """ Parse Markdown blocks into an ElementTree object. 
-    
+    """ Parse Markdown blocks into an ElementTree object.
+
     A wrapper class that stitches the various BlockProcessors together,
     looping through them and creating an ElementTree object.
     """
 
     def __init__(self, markdown):
         self.blockprocessors = odict.OrderedDict()
         self.state = State()
         self.markdown = markdown
 
     def parseDocument(self, lines):
-        """ Parse a markdown document into an ElementTree. 
-        
-        Given a list of lines, an ElementTree object (not just a parent Element)
-        is created and the root element is passed to the parser as the parent.
-        The ElementTree object is returned.
-        
+        """ Parse a markdown document into an ElementTree.
+
+        Given a list of lines, an ElementTree object (not just a parent
+        Element) is created and the root element is passed to the parser
+        as the parent. The ElementTree object is returned.
+
         This should only be called on an entire document, not pieces.
 
         """
         # Create a ElementTree from the lines
         self.root = util.etree.Element(self.markdown.doc_tag)
         self.parseChunk(self.root, '\n'.join(lines))
         return util.etree.ElementTree(self.root)
 
     def parseChunk(self, parent, text):
-        """ Parse a chunk of markdown text and attach to given etree node. 
-        
+        """ Parse a chunk of markdown text and attach to given etree node.
+
         While the ``text`` argument is generally assumed to contain multiple
         blocks which will be split on blank lines, it could contain only one
         block. Generally, this method would be called by extensions when
-        block parsing is required. 
-        
-        The ``parent`` etree Element passed in is altered in place. 
+        block parsing is required.
+
+        The ``parent`` etree Element passed in is altered in place.
         Nothing is returned.
 
         """
         self.parseBlocks(parent, text.split('\n\n'))
 
     def parseBlocks(self, parent, blocks):
-        """ Process blocks of markdown text and attach to given etree node. 
-        
+        """ Process blocks of markdown text and attach to given etree node.
+
         Given a list of ``blocks``, each blockprocessor is stepped through
         until there are no blocks left. While an extension could potentially
-        call this method directly, it's generally expected to be used internally.
+        call this method directly, it's generally expected to be used
+        internally.
 
-        This is a public method as an extension may need to add/alter additional
-        BlockProcessors which call this method to recursively parse a nested
-        block.
+        This is a public method as an extension may need to add/alter
+        additional BlockProcessors which call this method to recursively
+        parse a nested block.
 
         """
         while blocks:
             for processor in self.blockprocessors.values():
                 if processor.test(parent, blocks[0]):
                     if processor.run(parent, blocks) is not False:
                         # run returns True or None
                         break
-
-