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# :Id: $Id: tex2mathml_extern.py 9536 2024-02-01 13:04:22Z milde $
# :Copyright: © 2015 Günter Milde.
# :License: Released under the terms of the `2-Clause BSD license`__, in short:
#
# Copying and distribution of this file, with or without modification,
# are permitted in any medium without royalty provided the copyright
# notice and this notice are preserved.
# This file is offered as-is, without any warranty.
#
# __ https://opensource.org/licenses/BSD-2-Clause
"""Wrappers for TeX->MathML conversion by external tools
This module is provisional:
the API is not settled and may change with any minor Docutils version.
"""
import subprocess
from docutils import nodes
from docutils.utils.math import MathError, wrap_math_code
# `latexml` expects a complete document:
document_template = r"""\documentclass{article}
\begin{document}
%s
\end{document}
"""
def _check_result(result, details=[]):
# raise MathError if the conversion went wrong
# :details: list of doctree nodes with additional info
msg = ''
if not details and result.stderr:
details = [nodes.paragraph('', result.stderr, classes=['pre-wrap'])]
if details:
msg = f'TeX to MathML converter `{result.args[0]}` failed:'
elif result.returncode:
msg = (f'TeX to MathMl converter `{result.args[0]}` '
f'exited with Errno {result.returncode}.')
elif not result.stdout:
msg = f'TeX to MathML converter `{result.args[0]}` returned no MathML.'
if msg:
raise MathError(msg, details=details)
def blahtexml(math_code, as_block=False):
"""Convert LaTeX math code to MathML with blahtexml__.
__ http://gva.noekeon.org/blahtexml/
"""
args = ['blahtexml',
'--mathml',
'--indented',
'--spacing', 'moderate',
'--mathml-encoding', 'raw',
'--other-encoding', 'raw',
'--doctype-xhtml+mathml',
'--annotate-TeX',
]
# "blahtexml" expects LaTeX code without math-mode-switch.
# We still need to tell it about displayed equation(s).
mathml_args = ' display="block"' if as_block else ''
_wrapped = wrap_math_code(math_code, as_block)
if '{align*}' in _wrapped:
math_code = _wrapped.replace('{align*}', '{aligned}')
result = subprocess.run(args, input=math_code,
capture_output=True, text=True)
# blahtexml writes <error> messages to stdout
if '<error>' in result.stdout:
result.stderr = result.stdout[result.stdout.find('<message>')+9:
result.stdout.find('</message>')]
else:
result.stdout = result.stdout[result.stdout.find('<markup>')+9:
result.stdout.find('</markup>')]
_check_result(result)
return (f'<math xmlns="http://www.w3.org/1998/Math/MathML"{mathml_args}>'
f'\n{result.stdout}</math>')
def latexml(math_code, as_block=False):
"""Convert LaTeX math code to MathML with LaTeXML__.
Comprehensive macro support but **very** slow.
__ http://dlmf.nist.gov/LaTeXML/
"""
# LaTeXML works in 2 stages, expects complete documents.
#
# The `latexmlmath`__ convenience wrapper does not support block-level
# (displayed) equations.
#
# __ https://metacpan.org/dist/LaTeXML/view/bin/latexmlmath
args1 = ['latexml',
'-', # read from stdin
'--preload=amsmath',
'--preload=amssymb', # also loads amsfonts
'--inputencoding=utf8',
'--',
]
math_code = document_template % wrap_math_code(math_code, as_block)
result1 = subprocess.run(args1, input=math_code,
capture_output=True, text=True)
if result1.stderr:
result1.stderr = '\n'.join(line for line in result1.stderr.splitlines()
if line.startswith('Error:')
or line.startswith('Warning:')
or line.startswith('Fatal:'))
_check_result(result1)
args2 = ['latexmlpost',
'-',
'--nonumbersections',
'--format=html5', # maths included as MathML
'--omitdoctype', # Make it simple, we only need the maths.
'--noscan', # ...
'--nocrossref',
'--nographicimages',
'--nopictureimages',
'--nodefaultresources', # do not copy *.css files to output dir
'--'
]
result2 = subprocess.run(args2, input=result1.stdout,
capture_output=True, text=True)
# Extract MathML from HTML document:
# <table> with <math> in cells for "align", <math> element else.
start = result2.stdout.find('<table class="ltx_equationgroup')
if start != -1:
stop = result2.stdout.find('</table>', start)+8
result2.stdout = result2.stdout[start:stop].replace(
'ltx_equationgroup', 'borderless align-center')
else:
result2.stdout = result2.stdout[result2.stdout.find('<math'):
result2.stdout.find('</math>')+7]
# Search for error messages
if result2.stdout:
_msg_source = result2.stdout # latexmlpost reports errors in output
else:
_msg_source = result2.stderr # just in case
result2.stderr = '\n'.join(line for line in _msg_source.splitlines()
if line.startswith('Error:')
or line.startswith('Warning:')
or line.startswith('Fatal:'))
_check_result(result2)
return result2.stdout
def pandoc(math_code, as_block=False):
"""Convert LaTeX math code to MathML with pandoc__.
__ https://pandoc.org/
"""
args = ['pandoc',
'--mathml',
'--from=latex',
]
result = subprocess.run(args, input=wrap_math_code(math_code, as_block),
capture_output=True, text=True)
result.stdout = result.stdout[result.stdout.find('<math'):
result.stdout.find('</math>')+7]
# Pandoc (2.9.2.1) messages are pre-formatted for the terminal:
# 1. summary
# 2. math source (part)
# 3. error spot indicator '^' (works only in a literal block)
# 4. assumed problem
# 5. assumed solution (may be wrong or confusing)
# Construct a "details" list:
details = []
if result.stderr:
lines = result.stderr.splitlines()
details.append(nodes.paragraph('', lines[0]))
details.append(nodes.literal_block('', '\n'.join(lines[1:3])))
details.append(nodes.paragraph('', '\n'.join(lines[3:]),
classes=['pre-wrap']))
_check_result(result, details=details)
return result.stdout
def ttm(math_code, as_block=False):
"""Convert LaTeX math code to MathML with TtM__.
Aged, limited, but fast.
__ http://silas.psfc.mit.edu/tth/mml/
"""
args = ['ttm',
'-L', # source is LaTeX snippet
'-r'] # output MathML snippet
math_code = wrap_math_code(math_code, as_block)
# "ttm" does not support UTF-8 input. (Docutils converts most math
# characters to LaTeX commands before calling this function.)
try:
result = subprocess.run(args, input=math_code,
capture_output=True, text=True,
encoding='ISO-8859-1')
except UnicodeEncodeError as err:
raise MathError(err)
result.stdout = result.stdout[result.stdout.find('<math'):
result.stdout.find('</math>')+7]
if as_block:
result.stdout = result.stdout.replace('<math xmlns=',
'<math display="block" xmlns=')
result.stderr = '\n'.join(line[5:] + '.'
for line in result.stderr.splitlines()
if line.startswith('**** '))
_check_result(result)
return result.stdout
# self-test
if __name__ == "__main__":
example = (r'\frac{\partial \sin^2(\alpha)}{\partial \vec r}'
r'\varpi \mathbb{R} \, \text{Grüße}')
print("""<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<title>test external mathml converters</title>
</head>
<body>
<p>Test external converters</p>
<p>
""")
print(f'latexml: {latexml(example)},')
print(f'ttm: {ttm(example.replace("mathbb", "mathbf"))},')
print(f'blahtexml: {blahtexml(example)},')
print(f'pandoc: {pandoc(example)}.')
print('</p>')
print('<p>latexml:</p>')
print(latexml(example, as_block=True))
print('<p>ttm:</p>')
print(ttm(example.replace('mathbb', 'mathbf'), as_block=True))
print('<p>blahtexml:</p>')
print(blahtexml(example, as_block=True))
print('<p>pandoc:</p>')
print(pandoc(example, as_block=True))
print('</main>\n</body>\n</html>')
buggy = r'\sinc \phy'
# buggy = '\sqrt[e]'
try:
# print(blahtexml(buggy))
# print(latexml(f'${buggy}$'))
print(pandoc(f'${buggy}$'))
# print(ttm(f'${buggy}$'))
except MathError as err:
print(err)
print(err.details)
for node in err.details:
print(node.astext())
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