Files
edx-platform/lms/djangoapps/simplewiki/mdx_circuit.py
2012-07-23 14:44:40 -04:00

73 lines
2.6 KiB
Python
Executable File

#!/usr/bin/env python
'''
Image Circuit Extension for Python-Markdown
======================================
Any single line beginning with circuit-schematic: and followed by data (which should be json data, but this
is not enforced at this level) will be displayed as a circuit schematic. This is simply an input element with
the value set to the data. It is left to javascript on the page to render that input as a circuit schematic.
ex:
circuit-schematic:[["r",[128,48,0],{"r":"1","_json_":0},["2","1"]],["view",0,0,2,null,null,null,null,null,null,null],["dc",{"0":0,"1":1,"I(_3)":-1}]]
(This is a schematic with a single one-ohm resistor. Note that this data is not meant to be user-editable.)
'''
import markdown
import re
from django.utils.html import escape
try:
# Markdown 2.1.0 changed from 2.0.3. We try importing the new version first,
# but import the 2.0.3 version if it fails
from markdown.util import etree
except:
from markdown import etree
class CircuitExtension(markdown.Extension):
def __init__(self, configs):
for key, value in configs:
self.setConfig(key, value)
def extendMarkdown(self, md, md_globals):
## Because Markdown treats contigous lines as one block of text, it is hard to match
## a regex that must occupy the whole line (like the circuit regex). This is why we have
## a preprocessor that inspects the lines and replaces the matched lines with text that is
## easier to match
md.preprocessors.add('circuit', CircuitPreprocessor(md), "_begin")
pattern = CircuitLink(r'processed-schematic:(?P<data>.*?)processed-schematic-end')
pattern.md = md
pattern.ext = self
md.inlinePatterns.add('circuit', pattern, "<reference")
class CircuitPreprocessor(markdown.preprocessors.Preprocessor):
preRegex = re.compile(r'^circuit-schematic:(?P<data>.*)$')
def run(self, lines):
def convertLine(line):
m = self.preRegex.match(line)
if m:
return 'processed-schematic:{0}processed-schematic-end'.format(m.group('data'))
else:
return line
return [convertLine(line) for line in lines]
class CircuitLink(markdown.inlinepatterns.Pattern):
def handleMatch(self, m):
data = m.group('data')
data = escape(data)
return etree.fromstring("<div align='center'><input type='hidden' parts='' value='" + data + "' analyses='' class='schematic ctrls' width='640' height='480'/></div>")
def makeExtension(configs=None):
to_return = CircuitExtension(configs=configs)
print "circuit returning ", to_return
return to_return