r"""
Convert a restructured text document to html.
Inline math markup can uses the *math* directive, or it can use latex
style *\$expression\$*. Math can be rendered using simple html and
unicode, or with mathjax.
"""
import re
from contextlib import contextmanager
# CRUFT: locale.getlocale() fails on some versions of OS X
# See https://bugs.python.org/issue18378
import locale
if hasattr(locale, '_parse_localename'):
try:
locale._parse_localename('UTF-8')
except ValueError:
_old_parse_localename = locale._parse_localename
def _parse_localename(localename):
code = locale.normalize(localename)
if code == 'UTF-8':
return None, code
else:
return _old_parse_localename(localename)
locale._parse_localename = _parse_localename
from docutils.core import publish_parts
from docutils.writers.html4css1 import HTMLTranslator
from docutils.nodes import SkipNode
# pylint: disable=unused-import
try:
from typing import Tuple
except ImportError:
pass
# pylint: enable=unused-import
[docs]def rst2html(rst, part="whole", math_output="mathjax"):
r"""
Convert restructured text into simple html.
Valid *math_output* formats for formulas include:
- html
- mathml
- mathjax
See `<http://docutils.sourceforge.net/docs/user/config.html#math-output>`_
for details.
The following *part* choices are available:
- whole: the entire html document
- html_body: document division with title and contents and footer
- body: contents only
There are other parts, but they don't make sense alone:
subtitle, version, encoding, html_prolog, header, meta,
html_title, title, stylesheet, html_subtitle, html_body,
body, head, body_suffix, fragment, docinfo, html_head,
head_prefix, body_prefix, footer, body_pre_docinfo, whole
"""
# Ick! mathjax doesn't work properly with math-output, and the
# others don't work properly with math_output!
if math_output == "mathjax":
# TODO: this is copied from docs/conf.py; there should be only one
mathjax_path = "https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.1/MathJax.js?config=TeX-MML-AM_CHTML"
settings = {"math_output": math_output + " " + mathjax_path}
else:
settings = {"math-output": math_output}
# TODO: support stylesheets
#html_root = "/full/path/to/_static/"
#sheets = [html_root+s for s in ["basic.css","classic.css"]]
#settings["embed_styesheet"] = True
#settings["stylesheet_path"] = sheets
# math2html and mathml do not support \frac12
rst = replace_compact_fraction(rst)
# mathml, html do not support \tfrac
if math_output in ("mathml", "html"):
rst = rst.replace(r'\tfrac', r'\frac')
rst = replace_dollar(rst)
with suppress_html_errors():
parts = publish_parts(source=rst, writer_name='html',
settings_overrides=settings)
return parts[part]
[docs]@contextmanager
def suppress_html_errors():
r"""
Context manager for keeping error reports out of the generated HTML.
Within the context, system message nodes in the docutils parse tree
will be ignored. After the context, the usual behaviour will be restored.
"""
visit_system_message = HTMLTranslator.visit_system_message
HTMLTranslator.visit_system_message = _skip_node
yield None
HTMLTranslator.visit_system_message = visit_system_message
def _skip_node(self, node):
raise SkipNode
_compact_fraction = re.compile(r"(\\[cdt]?frac)([0-9])([0-9])")
[docs]def replace_compact_fraction(content):
r"""
Convert \frac12 to \frac{1}{2} for broken latex parsers
"""
return _compact_fraction.sub(r"\1{\2}{\3}", content)
_dollar = re.compile(r"(?:^|(?<=\s|[-(]))[$]([^\n]*?)(?<![\\])[$](?:$|(?=\s|[-.,;:?\\)]))")
_notdollar = re.compile(r"\\[$]")
[docs]def replace_dollar(content):
r"""
Convert dollar signs to inline math markup in rst.
"""
content = _dollar.sub(r":math:`\1`", content)
content = _notdollar.sub("$", content)
return content
[docs]def test_dollar():
"""
Test substitution of dollar signs with equivalent RST math markup
"""
assert replace_dollar(u"no dollar") == u"no dollar"
assert replace_dollar(u"$only$") == u":math:`only`"
assert replace_dollar(u"$first$ is good") == u":math:`first` is good"
assert replace_dollar(u"so is $last$") == u"so is :math:`last`"
assert replace_dollar(u"and $mid$ too") == u"and :math:`mid` too"
assert replace_dollar(u"$first$, $mid$, $last$") == u":math:`first`, :math:`mid`, :math:`last`"
assert replace_dollar(u"dollar\\$ escape") == u"dollar$ escape"
assert replace_dollar(u"dollar \\$escape\\$ too") == u"dollar $escape$ too"
assert replace_dollar(u"spaces $in the$ math") == u"spaces :math:`in the` math"
assert replace_dollar(u"emb\\ $ed$\\ ed") == u"emb\\ :math:`ed`\\ ed"
assert replace_dollar(u"$first$a") == u"$first$a"
assert replace_dollar(u"a$last$") == u"a$last$"
assert replace_dollar(u"$37") == u"$37"
assert replace_dollar(u"($37)") == u"($37)"
assert replace_dollar(u"$37 - $43") == u"$37 - $43"
assert replace_dollar(u"($37, $38)") == u"($37, $38)"
assert replace_dollar(u"a $mid$dle a") == u"a $mid$dle a"
assert replace_dollar(u"a ($in parens$) a") == u"a (:math:`in parens`) a"
assert replace_dollar(u"a (again $in parens$) a") == u"a (again :math:`in parens`) a"
[docs]def load_rst_as_html(filename):
# type: (str) -> str
"""Load rst from file and convert to html"""
from os.path import expanduser
with open(expanduser(filename)) as fid:
rst = fid.read()
html = rst2html(rst)
return html
[docs]def wxview(html, url="", size=(850, 540)):
# type: (str, str, Tuple[int, int]) -> "wx.Frame"
"""View HTML in a wx dialog"""
import wx
from wx.html2 import WebView
frame = wx.Frame(None, -1, size=size)
view = WebView.New(frame)
view.SetPage(html, url)
frame.Show()
return frame
[docs]def view_html_wxapp(html, url=""):
# type: (str, str) -> None
"""HTML viewer app in wx"""
import wx # type: ignore
app = wx.App()
frame = wxview(html, url) # pylint: disable=unused-variable
app.MainLoop()
[docs]def view_url_wxapp(url):
# type: (str) -> None
"""URL viewer app in wx"""
import wx # type: ignore
from wx.html2 import WebView
app = wx.App()
frame = wx.Frame(None, -1, size=(850, 540))
view = WebView.New(frame)
view.LoadURL(url)
frame.Show()
app.MainLoop()
[docs]def qtview(html, url=""):
# type: (str, str) -> "QWebView"
"""View HTML in a Qt dialog"""
try:
from PyQt5.QtWebKitWidgets import QWebView
from PyQt5.QtCore import QUrl
except ImportError:
from PyQt4.QtWebKit import QWebView
from PyQt4.QtCore import QUrl
helpView = QWebView()
helpView.setHtml(html, QUrl(url))
helpView.show()
return helpView
[docs]def view_html_qtapp(html, url=""):
# type: (str, str) -> None
"""HTML viewer app in Qt"""
import sys
try:
from PyQt5.QtWidgets import QApplication
except ImportError:
from PyQt4.QtGui import QApplication
app = QApplication([])
frame = qtview(html, url) # pylint: disable=unused-variable
sys.exit(app.exec_())
[docs]def view_url_qtapp(url):
# type: (str) -> None
"""URL viewer app in Qt"""
import sys
try:
from PyQt5.QtWidgets import QApplication
except ImportError:
from PyQt4.QtGui import QApplication
app = QApplication([])
try:
from PyQt5.QtWebKitWidgets import QWebView
from PyQt5.QtCore import QUrl
except ImportError:
from PyQt4.QtWebKit import QWebView
from PyQt4.QtCore import QUrl
frame = QWebView()
frame.load(QUrl(url))
frame.show()
sys.exit(app.exec_())
# Set default html viewer
view_html = view_html_qtapp
[docs]def can_use_qt():
# type: () -> bool
"""
Return True if QWebView exists.
Checks first in PyQt5 then in PyQt4
"""
try:
from PyQt5.QtWebKitWidgets import QWebView # pylint: disable=unused-import
return True
except ImportError:
try:
from PyQt4.QtWebKit import QWebView # pylint: disable=unused-import
return True
except ImportError:
return False
[docs]def view_help(filename, qt=False):
# type: (str, bool) -> None
"""View rst or html file. If *qt* use q viewer, otherwise use wx."""
import os
if qt:
qt = can_use_qt()
url = "file:///"+os.path.abspath(filename).replace("\\", "/")
if filename.endswith('.rst'):
html = load_rst_as_html(filename)
if qt:
view_html_qtapp(html, url)
else:
view_html_wxapp(html, url)
else:
if qt:
view_url_qtapp(url)
else:
view_url_wxapp(url)
[docs]def main():
# type: () -> None
"""Command line interface to rst or html viewer."""
import sys
view_help(sys.argv[1], qt=False)
if __name__ == "__main__":
main()