|
|
"""Latex filters.
|
|
|
|
|
|
Module of useful filters for processing Latex within Jinja latex templates.
|
|
|
"""
|
|
|
#-----------------------------------------------------------------------------
|
|
|
# Copyright (c) 2013, the IPython Development Team.
|
|
|
#
|
|
|
# Distributed under the terms of the Modified BSD License.
|
|
|
#
|
|
|
# The full license is in the file COPYING.txt, distributed with this software.
|
|
|
#-----------------------------------------------------------------------------
|
|
|
|
|
|
#-----------------------------------------------------------------------------
|
|
|
# Imports
|
|
|
#-----------------------------------------------------------------------------
|
|
|
import re
|
|
|
|
|
|
#-----------------------------------------------------------------------------
|
|
|
# Globals and constants
|
|
|
#-----------------------------------------------------------------------------
|
|
|
|
|
|
LATEX_RE_SUBS = (
|
|
|
(re.compile(r'\.\.\.+'), r'\\ldots'),
|
|
|
)
|
|
|
|
|
|
# Latex substitutions for escaping latex.
|
|
|
# see: http://stackoverflow.com/questions/16259923/how-can-i-escape-latex-special-characters-inside-django-templates
|
|
|
|
|
|
LATEX_SUBS = {
|
|
|
'&': r'\&',
|
|
|
'%': r'\%',
|
|
|
'$': r'\$',
|
|
|
'#': r'\#',
|
|
|
'_': r'\_',
|
|
|
'{': r'\{',
|
|
|
'}': r'\}',
|
|
|
'~': r'\textasciitilde{}',
|
|
|
'^': r'\^{}',
|
|
|
'\\': r'\textbackslash{}',
|
|
|
}
|
|
|
|
|
|
|
|
|
#-----------------------------------------------------------------------------
|
|
|
# Functions
|
|
|
#-----------------------------------------------------------------------------
|
|
|
|
|
|
__all__ = ['escape_latex',
|
|
|
'strip_math_space']
|
|
|
|
|
|
def escape_latex(text):
|
|
|
"""
|
|
|
Escape characters that may conflict with latex.
|
|
|
|
|
|
Parameters
|
|
|
----------
|
|
|
text : str
|
|
|
Text containing characters that may conflict with Latex
|
|
|
"""
|
|
|
text = ''.join(LATEX_SUBS.get(c, c) for c in text)
|
|
|
for pattern, replacement in LATEX_RE_SUBS:
|
|
|
text = pattern.sub(replacement, text)
|
|
|
|
|
|
return text
|
|
|
|
|
|
|
|
|
def strip_math_space(text):
|
|
|
"""
|
|
|
Remove the space between latex math commands and enclosing $ symbols.
|
|
|
This filter is important because latex isn't as flexible as the notebook
|
|
|
front end when it comes to flagging math using ampersand symbols.
|
|
|
|
|
|
Parameters
|
|
|
----------
|
|
|
text : str
|
|
|
Text to filter.
|
|
|
"""
|
|
|
|
|
|
# First, scan through the markdown looking for $. If
|
|
|
# a $ symbol is found, without a preceding \, assume
|
|
|
# it is the start of a math block. UNLESS that $ is
|
|
|
# not followed by another within two math_lines.
|
|
|
math_regions = []
|
|
|
math_lines = 0
|
|
|
within_math = False
|
|
|
math_start_index = 0
|
|
|
ptext = ''
|
|
|
last_character = ""
|
|
|
skip = False
|
|
|
for index, char in enumerate(text):
|
|
|
|
|
|
#Make sure the character isn't preceeded by a backslash
|
|
|
if (char == "$" and last_character != "\\"):
|
|
|
|
|
|
# Close the math region if this is an ending $
|
|
|
if within_math:
|
|
|
within_math = False
|
|
|
skip = True
|
|
|
ptext = ptext+'$'+text[math_start_index+1:index].strip()+'$'
|
|
|
math_regions.append([math_start_index, index+1])
|
|
|
else:
|
|
|
|
|
|
# Start a new math region
|
|
|
within_math = True
|
|
|
math_start_index = index
|
|
|
math_lines = 0
|
|
|
|
|
|
# If we are in a math region, count the number of lines parsed.
|
|
|
# Cancel the math region if we find two line breaks!
|
|
|
elif char == "\n":
|
|
|
if within_math:
|
|
|
math_lines += 1
|
|
|
if math_lines > 1:
|
|
|
within_math = False
|
|
|
ptext = ptext+text[math_start_index:index]
|
|
|
|
|
|
# Remember the last character so we can easily watch
|
|
|
# for backslashes
|
|
|
last_character = char
|
|
|
if not within_math and not skip:
|
|
|
ptext = ptext+char
|
|
|
if skip:
|
|
|
skip = False
|
|
|
return ptext
|
|
|
|
