Snippet include file brefore/after label

[astromatt]

Description

I am converting my 5000 pages (yes, 5k pages) Python training materials from ReST to Markdown and I would like to replicate behavior of literalinclude tag:

.. literalinclude:: myfile.py
    :caption: :download:`Solution <myfile.py>`
    :end-before: # Solution

So, that I can include file content from the first line until the desired label (in this case comment "# Solution"). I cannot use numeric slices, because solution lengths are variable for each assignment I have in my materials.

Benefits

Ability to include only part of the file.

Solution Idea

--8<-- "myfile.py" before:"# Solution"

or

--8<-- "myfile.py">"# Solution"

or

--8<-- "myfile.py":>"# Solution"

Also mind, that one-liner (including fence) syntax for Snippets would be nice:

`--8<-- "myfile.py" before:"# Solution"`

[astromatt]

I wrote small extension for SuperFences:

File myproject/extensions/include.py:

import re
from pathlib import Path
from pymdownx.superfences import SuperFencesException


def formatter(source, language, css_class, options, md, **kwargs):
    file = re.search(r'file="(.+)"', source).group(1)
    before = re.search(r'before="(.+)"', source).group(1)
    path = Path(__file__).parent.parent / 'docs' / file
    if not path.exists():
        raise SuperFencesException(f'File {path} does not exist')
    content = path.read_text()
    if before not in content:
        raise SuperFencesException(f'File {path} does not contain {before}')
    assignment, solution = content.split(before)
    return f"<pre><code>{assignment}</code></pre>"

File myproject/mkdocs.yml:

  - pymdownx.superfences:
      custom_fences:
        - name: include
          class: include
          format: !!python/name:extensions.include.formatter

File myproject/docs/myfile.md:

\```include
file="assignments/myfile.py"
before="# Solution"
\```

Of course without escaping the ` (ticks, fences) characters.

It works, but I am struggling with code highlighting, adding title (to work the same as regular title for fence) and getting an absolute path of a file which triggered my function.

If I do:

<div class="language-python highlight">
    <span class="filename">{path.stem}</span>
    <pre>
    <code>{assignment}</code>
    </pre>
</div>

Then in output HTML there is a blank line between title and code block.
Code highlighting doesn't work at all.

Any help appreciated :)

[facelessuser]

@astromatt

Just wrap your logic around the default highlighter.

1. I changed the path handling just to make it easier for me to throw together the example. It looks in the same folder as the script. You can change it back to what you were doing.
2. Use the default highlight validator to get the same options.
3. Wrap your logic around the default validator.

import re
from pathlib import Path
from pymdownx.superfences import SuperFencesException, highlight_validator
import markdown

MD = """
```include title="Title"
file="myfile.py"
before="# Solution"
```
"""

def formatter(source, language, css_class, options, md, **kwargs):
    file = re.search(r'file="(.+)"', source).group(1)
    before = re.search(r'before="(.+)"', source).group(1)
    path = Path(__file__).parent / file
    if not path.exists():
        raise SuperFencesException(f'File {path} does not exist')
    content = path.read_text()
    if before not in content:
        raise SuperFencesException(f'File {path} does not contain {before}')
    assignment, solution = content.split(before)

    return md.preprocessors['fenced_code_block'].highlight(
        src=assignment,
        class_name=css_class,
        language='python',
        md=md,
        options=options,
        **kwargs
    )


html = markdown.markdown(
    MD,
    extensions=['pymdownx.superfences'],
    extension_configs={
        'pymdownx.superfences': {
            'custom_fences': [
                {
                    'name': 'include',
                    'class': 'inlcude',
                    'format': formatter,
                    'validator': highlight_validator
                }
            ]
        }
    }
)

print(html)

myfile.py

print('hello world') # Solution

Results

<div class="highlight"><span class="filename">Title</span><pre><span></span><code><span class="nb">print</span><span class="p">(</span><span class="s1">&#39;hello world&#39;</span><span class="p">)</span>
</code></pre></div>