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# -*- coding: utf-8 -*-
"""
Pelican Mathjax Markdown Extension
==================================
An extension for the Python Markdown module that enables
the Pelican python blog to process mathjax. This extension
gives Pelican the ability to use Mathjax as a "first class
citizen" of the blog
"""
from xml.etree.ElementTree import Element
import markdown
from markdown.util import AtomicString
class PelicanMathJaxPattern(markdown.inlinepatterns.Pattern):
"""Inline markdown processing that matches mathjax"""
def __init__(self, pelican_mathjax_extension, tag, pattern):
super(PelicanMathJaxPattern, self).__init__(pattern)
self.math_tag_class = pelican_mathjax_extension.getConfig("math_tag_class")
self.pelican_mathjax_extension = pelican_mathjax_extension
self.tag = tag
def handleMatch(self, m):
node = Element(self.tag)
node.set("class", self.math_tag_class)
prefix = "\\(" if m.group("prefix") == "$" else m.group("prefix")
suffix = "\\)" if m.group("suffix") == "$" else m.group("suffix")
node.text = markdown.util.AtomicString(prefix + m.group("math") + suffix)
# If mathjax was successfully matched, then JavaScript needs to be added
# for rendering. The boolean below indicates this
self.pelican_mathjax_extension.mathjax_needed = True
return node
class PelicanMathJaxCorrectDisplayMath(markdown.treeprocessors.Treeprocessor):
"""Corrects invalid html that results from a <div> being put inside
a <p> for displayed math"""
def __init__(self, pelican_mathjax_extension):
self.pelican_mathjax_extension = pelican_mathjax_extension
def correct_html(self, root, children, div_math, insert_idx, text):
"""Separates out <div class="math"> from the parent tag <p>. Anything
in between is put into its own parent tag of <p>"""
current_idx = 0
for idx in div_math:
el = Element("p")
el.text = text
el.extend(children[current_idx:idx])
# Test to ensure that empty <p> is not inserted
if len(el) != 0 or (el.text and not el.text.isspace()):
root.insert(insert_idx, el)
insert_idx += 1
text = children[idx].tail
children[idx].tail = None
root.insert(insert_idx, children[idx])
insert_idx += 1
current_idx = idx + 1
el = Element("p")
el.text = text
el.extend(children[current_idx:])
if len(el) != 0 or (el.text and not el.text.isspace()):
root.insert(insert_idx, el)
def run(self, root):
"""Searches for <div class="math"> that are children in <p> tags and corrects
the invalid HTML that results"""
math_tag_class = self.pelican_mathjax_extension.getConfig("math_tag_class")
for parent in root:
div_math = []
children = list(parent)
for div in parent.findall("div"):
if div.get("class") == math_tag_class:
div_math.append(children.index(div))
# Do not process further if no displayed math has been found
if not div_math:
continue
insert_idx = list(root).index(parent)
self.correct_html(root, children, div_math, insert_idx, parent.text)
root.remove(
parent
) # Parent must be removed last for correct insertion index
return root
class PelicanMathJaxAddJavaScript(markdown.treeprocessors.Treeprocessor):
"""Tree Processor for adding Mathjax JavaScript to the blog"""
def __init__(self, pelican_mathjax_extension):
self.pelican_mathjax_extension = pelican_mathjax_extension
def run(self, root):
# If no mathjax was present, then exit
if not self.pelican_mathjax_extension.mathjax_needed:
return root
# Add the mathjax script to the html document
mathjax_script = Element("script")
mathjax_script.set("type", "text/javascript")
mathjax_script.text = AtomicString(
self.pelican_mathjax_extension.getConfig("mathjax_script")
)
root.append(mathjax_script)
# Reset the boolean switch to false so that script is only added
# to other pages if needed
self.pelican_mathjax_extension.mathjax_needed = False
return root
class PelicanMathJaxExtension(markdown.Extension):
"""A markdown extension enabling mathjax processing in Markdown for Pelican"""
def __init__(self, config):
try:
# Needed for markdown versions >= 2.5
self.config["mathjax_script"] = ["", "Mathjax JavaScript script"]
self.config["math_tag_class"] = [
"math",
"The class of the tag in which mathematics is wrapped",
]
self.config["auto_insert"] = [
True,
"Determines if mathjax script is automatically inserted into content",
]
super(PelicanMathJaxExtension, self).__init__(**config)
except AttributeError:
# Markdown versions < 2.5
config["mathjax_script"] = [
config["mathjax_script"],
"Mathjax JavaScript script",
]
config["math_tag_class"] = [
config["math_tag_class"],
"The class of the tag in which mathematic is wrapped",
]
config["auto_insert"] = [
config["auto_insert"],
"Determines if mathjax script is automatically inserted into content",
]
super(PelicanMathJaxExtension, self).__init__(config)
# Used as a flag to determine if javascript
# needs to be injected into a document
self.mathjax_needed = False
def extendMarkdown(self, md):
# Regex to detect mathjax
mathjax_inline_regex = r"(?P<prefix>\$)(?P<math>.+?)(?P<suffix>(?<!\s)\2)"
mathjax_display_regex = (
r"(?P<prefix>\$\$|\\begin\{(.+?)\})(?P<math>.+?)(?P<suffix>\2|\\end\{\3\})"
)
# Process mathjax before escapes are processed since escape processing will
# intefer with mathjax. The order in which the displayed and inlined math
# is registered below matters: we should have higher priority than 'escape' which has 180
md.inlinePatterns.register(
PelicanMathJaxPattern(self, "div", mathjax_display_regex),
"mathjax_displayed",
186,
)
md.inlinePatterns.register(
PelicanMathJaxPattern(self, "span", mathjax_inline_regex),
"mathjax_inlined",
185,
)
# Correct the invalid HTML that results from teh displayed math (<div> tag within a <p> tag)
md.treeprocessors.register(
PelicanMathJaxCorrectDisplayMath(self), "mathjax_correctdisplayedmath", 15
)
# If necessary, add the JavaScript Mathjax library to the document. This must
# be last in the ordered dict (hence it is given the position '_end')
if self.getConfig("auto_insert"):
md.treeprocessors.register(
PelicanMathJaxAddJavaScript(self), "mathjax_addjavascript", 0
)
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