import logging
import re
import string
import bibtexparser
import traitlets as traits
from nbconvert.preprocessors import Preprocessor
# python 3 to 2 compatibility
try:
basestring
except NameError:
basestring = str
[docs]class LatexTagsToHTML(Preprocessor):
r""" a preprocessor to find latex tags (like \cite{abc} or \todo[color]{stuff}) and:
1. attempt to process them into a html friendly format
2. remove them entirely if this is not possible
for \ref or \cref, attempts to use resources.refmap to map labels to reference names
for labels not found in resources.refmap
the reference name is '<name> <number>', where;
- <name> is either ref of, if labelbycolon is True and the label has a colon, all text before the colon
- <number> iterate by order of first appearance of a particular label
NB: should be applied after LatexDocHTML, if you want resources.refmap to be available
Examples
--------
>>> from nbformat import NotebookNode
>>> from jsonextended.utils import MockPath
>>> processor = LatexTagsToHTML()
>>> bibfile = MockPath(is_file=True,content='''
... @article{bibkey,
... title = {the title},
... doi = {10.1134/S0018143916050209},
... author = {Surname, A. Name},
... date = {2016-09-01},
... }
... ''')
>>> resources = NotebookNode({'bibliopath':bibfile, 'refmap':{"label":"label_name"}})
>>> cell = NotebookNode({
... "cell_type":"markdown",
... "metadata":{},
... "source":"test"
... })
>>> nb = NotebookNode({"cells":[cell]})
>>> nb, _ = processor.preprocess(nb,resources)
>>> print(nb.cells[0].source)
test
>>> cell.source = "\\unknown{test}"
>>> nb, _ = processor.preprocess(nb,resources)
>>> print(nb.cells[0].source)
<BLANKLINE>
>>> cell.source = "\\ref{label}\\unknown{test}"
>>> nb, _ = processor.preprocess(nb,resources)
>>> print(nb.cells[0].source)
<a href="{id_home_prefix}label">label_name</a>
>>> cell.source = "\\label{test}"
>>> nb, _ = processor.preprocess(nb,resources)
>>> print(nb.cells[0].source)
<a id="test" class="anchor-link" name="#test">¶</a>
>>> cell.source = "\\cite{bibkey}"
>>> nb, _ = processor.preprocess(nb,resources)
>>> print(nb.cells[0].source)
[<a href="https://doi.org/10.1134/S0018143916050209">Surname <em>et al</em>, 2016.</a>]
>>> cell.source = "\\begin{equation}x=a+b\\end{equation}"
>>> nb, _ = processor.preprocess(nb,resources)
>>> print(nb.cells[0].source)
\begin{equation}x=a+b\end{equation}
"""
regex = traits.Unicode(r"\\(?:[^a-zA-Z]|[a-zA-Z]+[*=']?)(?:\[.*?\])?{.*?}",
help="the regex to identify latex tags").tag(config=True)
bibformat = traits.Unicode("{author}, {year}.",
help=r"the format to output \cite{} tags found in the bibliography").tag(config=True)
labelbycolon = traits.Bool(True,
help=r'create reference label based on text before colon, e.g. \ref{fig:example} -> fig 1').tag(
config=True)
def __init__(self, *args, **kwargs):
# a dictionary to keep track of references, so they each get a different number
self.refs = {}
# bibliography references
self.bibdatabase = {}
super(LatexTagsToHTML, self).__init__(*args, **kwargs)
[docs] @staticmethod
def read_bibliography(path):
""" read a bibliography
"""
logging.info('reading bibliopath: {}'.format(path))
bibdatabase = {}
try:
if hasattr(path,'open'):
with path.open() as bibtex_file:
bibdatabase = bibtexparser.load(bibtex_file).entries_dict
else:
with open(path) as bibtex_file:
bibdatabase = bibtexparser.load(bibtex_file).entries_dict
except:
logging.error('could not read bibliopath: {}'.format(path))
return bibdatabase
[docs] def rreplace(self, source, target, replacement, replacements=1):
"""replace in string, from right-to-left"""
return replacement.join(source.rsplit(target, replacements))
[docs] def process_bib_entry(self, entry):
"""work out the best way to represent the bib entry """
# abbreviate a list of authors
if 'author' in entry:
authors = re.split(", | and ", entry['author'])
if len(authors) > 1:
author = authors[0] + ' <em>et al</em>'
else:
author = authors[0]
entry['author'] = author
# split up date into year, month, day
if 'date' in entry:
date = entry['date'].split('-')
if len(date) == 3:
entry['year'] = date[0]
entry['month'] = date[1]
entry['day'] = date[2]
else:
entry['year'] = date[0]
text = DefaultFormatter().format(self.bibformat, **entry)
if 'doi' in entry:
return r'<a href="https://doi.org/{doi}">{text}</a>'.format(doi=entry['doi'], text=text)
elif 'url' in entry:
return r'<a href="{url}">{text}</a>'.format(url=entry['url'], text=text)
elif 'link' in entry:
return r'<a href="{url}">{text}</a>'.format(url=entry['link'], text=text)
else:
return text
[docs] def replace_reflabel(self, name, resources):
""" find a suitable html replacement for a reference label
the links are left with a format hook in them: {id_home_prefix},
so that an nbconvert filter can later replace it
this is particularly useful for slides, which require a prefix #/<slide_number><label>
"""
if 'refmap' in resources:
if name in resources['refmap']:
return r'<a href="{{id_home_prefix}}{0}">{1}</a>'.format(name, resources['refmap'][name])
if self.labelbycolon:
ref_name = name.split(':')[0] if ':' in name else 'ref'
else:
ref_name = 'ref'
if not ref_name in self.refs:
self.refs[ref_name] = {}
refs = self.refs[ref_name]
if name in refs:
id = refs[name]
else:
id = len(refs) + 1
refs[name] = id
return r'<a href="{{id_home_prefix}}{0}">{1}. {2}</a>'.format(name, ref_name, id)
[docs] def convert(self, source, resources):
""" convert a a string with tags in
Example
-------
>>> source = r'''
... References to \\cref{fig:example}, \\cref{tbl:example}, \\cref{eqn:example_sympy} and \\cref{code:example_mpl}.
...
... Referencing multiple items: \\cref{fig:example,fig:example_h,fig:example_v}.
...
... An unknown latex tag.\\unknown{zelenyak_molecular_2016}
... '''
>>> processor = LatexTagsToHTML()
>>> print(processor.convert(source,{}))
<BLANKLINE>
References to <a href="{id_home_prefix}fig:example">fig. 1</a>, <a href="{id_home_prefix}tbl:example">tbl. 1</a>, <a href="{id_home_prefix}eqn:example_sympy">eqn. 1</a> and <a href="{id_home_prefix}code:example_mpl">code. 1</a>.
<BLANKLINE>
Referencing multiple items: <a href="{id_home_prefix}fig:example">fig. 1</a>, <a href="{id_home_prefix}fig:example_h">fig. 2</a> and <a href="{id_home_prefix}fig:example_v">fig. 3</a>.
<BLANKLINE>
An unknown latex tag.
<BLANKLINE>
"""
new = source
in_equation = False
labels = []
for tag in re.findall(self.regex, source):
if tag.startswith('\\label'):
link = r'<a id="{label}" class="anchor-link" name="#{label}">¶</a>'.format(label=tag[7:-1])
if in_equation:
labels.append(link)
new = new.replace(tag, '')
else:
new = new.replace(tag, link)
elif tag.startswith('\\ref'):
names = tag[5:-1].split(',')
html = []
for name in names:
html.append(self.replace_reflabel(name, resources))
new = new.replace(tag, self.rreplace(', '.join(html), ',', ' and'))
elif tag.startswith('\\cref'):
names = tag[6:-1].split(',')
html = []
for name in names:
html.append(self.replace_reflabel(name, resources))
new = new.replace(tag, self.rreplace(', '.join(html), ',', ' and'))
elif tag.startswith('\\cite'):
names = tag[6:-1].split(',')
html = []
for name in names:
if name in self.bibdatabase:
html.append(self.process_bib_entry(self.bibdatabase[name]))
else:
html.append('Unresolved citation: {}.'.format(name))
new = new.replace(tag, '[' + ', '.join(html) + ']')
elif any([tag.startswith('\\begin{{{0}}}'.format(env)) for env in
['equation', 'equation*', 'align', 'align*', 'multline', 'multline*', 'gather', 'gather*']]):
in_equation = True
elif any([tag.startswith('\\end{{{0}}}'.format(env)) for env in
['equation', 'equation*', 'align', 'align*', 'multline', 'multline*', 'gather', 'gather*']]):
new += ' '.join(labels)
labels = []
in_equation = False
elif any([tag.startswith('\\begin{{{0}}}'.format(env)) for env in
['split']]):
pass
elif any([tag.startswith('\\end{{{0}}}'.format(env)) for env in
['split']]):
pass
else:
new = new.replace(tag, '')
return new
[docs] def preprocess(self, nb, resources):
logging.info('converting latex tags to html')
if 'bibliopath' in resources:
self.bibdatabase = self.read_bibliography(resources['bibliopath'])
else:
self.bibdatabase = {}
for cell in nb.cells:
if "ipub" in cell['metadata']:
for key in cell['metadata']["ipub"]:
if not isinstance(cell['metadata']["ipub"][key], dict):
continue
if "caption" in cell['metadata']["ipub"][key]:
text = cell['metadata']["ipub"][key]["caption"]
cell['metadata']["ipub"][key]["caption"] = self.convert(text, resources)
if not cell['cell_type'] == "markdown":
continue
cell['source'] = self.convert(cell['source'], resources)
resources['refslide'] = {}
return nb, resources