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Python

# CodeHilite Extension for Python-Markdown
# ========================================
# Adds code/syntax highlighting to standard Python-Markdown code blocks.
# See https://Python-Markdown.github.io/extensions/code_hilite
# for documentation.
# Original code Copyright 2006-2008 [Waylan Limberg](http://achinghead.com/).
# All changes Copyright 2008-2014 The Python Markdown Project
# License: [BSD](https://opensource.org/licenses/bsd-license.php)
"""
Adds code/syntax highlighting to standard Python-Markdown code blocks.
See the [documentation](https://Python-Markdown.github.io/extensions/code_hilite)
for details.
"""
from __future__ import annotations
from . import Extension
from ..treeprocessors import Treeprocessor
from ..util import parseBoolValue
from typing import TYPE_CHECKING, Callable, Any
if TYPE_CHECKING: # pragma: no cover
import xml.etree.ElementTree as etree
try: # pragma: no cover
from pygments import highlight
from pygments.lexers import get_lexer_by_name, guess_lexer
from pygments.formatters import get_formatter_by_name
from pygments.util import ClassNotFound
pygments = True
except ImportError: # pragma: no cover
pygments = False
def parse_hl_lines(expr: str) -> list[int]:
"""Support our syntax for emphasizing certain lines of code.
`expr` should be like '1 2' to emphasize lines 1 and 2 of a code block.
Returns a list of integers, the line numbers to emphasize.
"""
if not expr:
return []
try:
return list(map(int, expr.split()))
except ValueError: # pragma: no cover
return []
# ------------------ The Main CodeHilite Class ----------------------
class CodeHilite:
"""
Determine language of source code, and pass it on to the Pygments highlighter.
Usage:
```python
code = CodeHilite(src=some_code, lang='python')
html = code.hilite()
```
Arguments:
src: Source string or any object with a `.readline` attribute.
Keyword arguments:
lang (str): String name of Pygments lexer to use for highlighting. Default: `None`.
guess_lang (bool): Auto-detect which lexer to use.
Ignored if `lang` is set to a valid value. Default: `True`.
use_pygments (bool): Pass code to Pygments for code highlighting. If `False`, the code is
instead wrapped for highlighting by a JavaScript library. Default: `True`.
pygments_formatter (str): The name of a Pygments formatter or a formatter class used for
highlighting the code blocks. Default: `html`.
linenums (bool): An alias to Pygments `linenos` formatter option. Default: `None`.
css_class (str): An alias to Pygments `cssclass` formatter option. Default: 'codehilite'.
lang_prefix (str): Prefix prepended to the language. Default: "language-".
Other Options:
Any other options are accepted and passed on to the lexer and formatter. Therefore,
valid options include any options which are accepted by the `html` formatter or
whichever lexer the code's language uses. Note that most lexers do not have any
options. However, a few have very useful options, such as PHP's `startinline` option.
Any invalid options are ignored without error.
* **Formatter options**: <https://pygments.org/docs/formatters/#HtmlFormatter>
* **Lexer Options**: <https://pygments.org/docs/lexers/>
Additionally, when Pygments is enabled, the code's language is passed to the
formatter as an extra option `lang_str`, whose value being `{lang_prefix}{lang}`.
This option has no effect to the Pygments' builtin formatters.
Advanced Usage:
```python
code = CodeHilite(
src = some_code,
lang = 'php',
startinline = True, # Lexer option. Snippet does not start with `<?php`.
linenostart = 42, # Formatter option. Snippet starts on line 42.
hl_lines = [45, 49, 50], # Formatter option. Highlight lines 45, 49, and 50.
linenos = 'inline' # Formatter option. Avoid alignment problems.
)
html = code.hilite()
```
"""
def __init__(self, src: str, **options):
self.src = src
self.lang: str | None = options.pop('lang', None)
self.guess_lang: bool = options.pop('guess_lang', True)
self.use_pygments: bool = options.pop('use_pygments', True)
self.lang_prefix: str = options.pop('lang_prefix', 'language-')
self.pygments_formatter: str | Callable = options.pop('pygments_formatter', 'html')
if 'linenos' not in options:
options['linenos'] = options.pop('linenums', None)
if 'cssclass' not in options:
options['cssclass'] = options.pop('css_class', 'codehilite')
if 'wrapcode' not in options:
# Override Pygments default
options['wrapcode'] = True
# Disallow use of `full` option
options['full'] = False
self.options = options
def hilite(self, shebang: bool = True) -> str:
"""
Pass code to the [Pygments](https://pygments.org/) highlighter with
optional line numbers. The output should then be styled with CSS to
your liking. No styles are applied by default - only styling hooks
(i.e.: `<span class="k">`).
returns : A string of html.
"""
self.src = self.src.strip('\n')
if self.lang is None and shebang:
self._parseHeader()
if pygments and self.use_pygments:
try:
lexer = get_lexer_by_name(self.lang, **self.options)
except ValueError:
try:
if self.guess_lang:
lexer = guess_lexer(self.src, **self.options)
else:
lexer = get_lexer_by_name('text', **self.options)
except ValueError: # pragma: no cover
lexer = get_lexer_by_name('text', **self.options)
if not self.lang:
# Use the guessed lexer's language instead
self.lang = lexer.aliases[0]
lang_str = f'{self.lang_prefix}{self.lang}'
if isinstance(self.pygments_formatter, str):
try:
formatter = get_formatter_by_name(self.pygments_formatter, **self.options)
except ClassNotFound:
formatter = get_formatter_by_name('html', **self.options)
else:
formatter = self.pygments_formatter(lang_str=lang_str, **self.options)
return highlight(self.src, lexer, formatter)
else:
# just escape and build markup usable by JavaScript highlighting libraries
txt = self.src.replace('&', '&amp;')
txt = txt.replace('<', '&lt;')
txt = txt.replace('>', '&gt;')
txt = txt.replace('"', '&quot;')
classes = []
if self.lang:
classes.append('{}{}'.format(self.lang_prefix, self.lang))
if self.options['linenos']:
classes.append('linenums')
class_str = ''
if classes:
class_str = ' class="{}"'.format(' '.join(classes))
return '<pre class="{}"><code{}>{}\n</code></pre>\n'.format(
self.options['cssclass'],
class_str,
txt
)
def _parseHeader(self) -> None:
"""
Determines language of a code block from shebang line and whether the
said line should be removed or left in place. If the shebang line
contains a path (even a single /) then it is assumed to be a real
shebang line and left alone. However, if no path is given
(e.i.: `#!python` or `:::python`) then it is assumed to be a mock shebang
for language identification of a code fragment and removed from the
code block prior to processing for code highlighting. When a mock
shebang (e.i: `#!python`) is found, line numbering is turned on. When
colons are found in place of a shebang (e.i.: `:::python`), line
numbering is left in the current state - off by default.
Also parses optional list of highlight lines, like:
:::python hl_lines="1 3"
"""
import re
# split text into lines
lines = self.src.split("\n")
# pull first line to examine
fl = lines.pop(0)
c = re.compile(r'''
(?:(?:^::+)|(?P<shebang>^[#]!)) # Shebang or 2 or more colons
(?P<path>(?:/\w+)*[/ ])? # Zero or 1 path
(?P<lang>[\w#.+-]*) # The language
\s* # Arbitrary whitespace
# Optional highlight lines, single- or double-quote-delimited
(hl_lines=(?P<quot>"|')(?P<hl_lines>.*?)(?P=quot))?
''', re.VERBOSE)
# search first line for shebang
m = c.search(fl)
if m:
# we have a match
try:
self.lang = m.group('lang').lower()
except IndexError: # pragma: no cover
self.lang = None
if m.group('path'):
# path exists - restore first line
lines.insert(0, fl)
if self.options['linenos'] is None and m.group('shebang'):
# Overridable and Shebang exists - use line numbers
self.options['linenos'] = True
self.options['hl_lines'] = parse_hl_lines(m.group('hl_lines'))
else:
# No match
lines.insert(0, fl)
self.src = "\n".join(lines).strip("\n")
# ------------------ The Markdown Extension -------------------------------
class HiliteTreeprocessor(Treeprocessor):
""" Highlight source code in code blocks. """
config: dict[str, Any]
def code_unescape(self, text: str) -> str:
"""Unescape code."""
text = text.replace("&lt;", "<")
text = text.replace("&gt;", ">")
# Escaped '&' should be replaced at the end to avoid
# conflicting with < and >.
text = text.replace("&amp;", "&")
return text
def run(self, root: etree.Element) -> None:
""" Find code blocks and store in `htmlStash`. """
blocks = root.iter('pre')
for block in blocks:
if len(block) == 1 and block[0].tag == 'code':
local_config = self.config.copy()
text = block[0].text
if text is None:
continue
code = CodeHilite(
self.code_unescape(text),
tab_length=self.md.tab_length,
style=local_config.pop('pygments_style', 'default'),
**local_config
)
placeholder = self.md.htmlStash.store(code.hilite())
# Clear code block in `etree` instance
block.clear()
# Change to `p` element which will later
# be removed when inserting raw html
block.tag = 'p'
block.text = placeholder
class CodeHiliteExtension(Extension):
""" Add source code highlighting to markdown code blocks. """
def __init__(self, **kwargs):
# define default configs
self.config = {
'linenums': [
None, "Use lines numbers. True|table|inline=yes, False=no, None=auto. Default: `None`."
],
'guess_lang': [
True, "Automatic language detection - Default: `True`."
],
'css_class': [
"codehilite", "Set class name for wrapper <div> - Default: `codehilite`."
],
'pygments_style': [
'default', 'Pygments HTML Formatter Style (Colorscheme). Default: `default`.'
],
'noclasses': [
False, 'Use inline styles instead of CSS classes - Default `False`.'
],
'use_pygments': [
True, 'Highlight code blocks with pygments. Disable if using a JavaScript library. Default: `True`.'
],
'lang_prefix': [
'language-', 'Prefix prepended to the language when `use_pygments` is false. Default: `language-`.'
],
'pygments_formatter': [
'html', 'Use a specific formatter for Pygments highlighting. Default: `html`.'
],
}
""" Default configuration options. """
for key, value in kwargs.items():
if key in self.config:
self.setConfig(key, value)
else:
# manually set unknown keywords.
if isinstance(value, str):
try:
# Attempt to parse `str` as a boolean value
value = parseBoolValue(value, preserve_none=True)
except ValueError:
pass # Assume it's not a boolean value. Use as-is.
self.config[key] = [value, '']
def extendMarkdown(self, md):
""" Add `HilitePostprocessor` to Markdown instance. """
hiliter = HiliteTreeprocessor(md)
hiliter.config = self.getConfigs()
md.treeprocessors.register(hiliter, 'hilite', 30)
md.registerExtension(self)
def makeExtension(**kwargs): # pragma: no cover
return CodeHiliteExtension(**kwargs)