A custom superfence for pymdown-extensions that can filters lines and plays nice with MkDocs.

This is particularly useful when you want to hide some comments or some boilerplate code from the documentation for any reason.

A typical use case is when you are testing your examples in the documentation, so you might need to add some initialization code, or importing some dependencies that are not relevant for the point you are trying to make in the documentation, but you still need the example code to work to make sure they are not inadvertedly broken.

When writing some documentation, and you want to show some code block, but you want to show only some lines, you can use this superfence as follows:

```text show_lines=":2,4,7,10:12,15:"
This is line 1
This is line 2
This is line 3
This is line 4
This is line 5
This is line 6
This is line 7
This is line 8
This is line 9
This is line 10
This is line 11
This is line 12
This is line 13
This is line 14
This is line 15
This is line 16
This is line 17
```

This will show the following block of code in the rendered output:

This is line 1
This is line 2
This is line 3
This is line 4
This is line 5
This is line 6
This is line 7
This is line 8
This is line 9
This is line 10
This is line 11
This is line 12
This is line 13
This is line 14
This is line 15
This is line 16
This is line 17

See Usage for a more detailed explanation of the available options.

To use this superfence with MkDocs, you can use something like this:

markdown_extensions:
  - pymdownx.superfences:
      custom_fences:
        - name: "*"
          class: "highlight"
          format: !!python/name:pymdownx_superfence_filter_lines.do_format
          validator: !!python/name:pymdownx_superfence_filter_lines.do_validate

To use this superfence standalone, you can use something like this:

import markdown
from pymdownx_superfence_filter_lines import do_format, do_validate

html = markdown.markdown(
    markdown_source,
    extensions=['pymdownx.superfence'],
    extension_configs={
        "pymdownx.superfences": {
            "custom_fences": [
                {
                    'name': '*',
                    'class': 'highlight',
                    'validator': do_validate,
                    'format': do_format
                }
            ]
        }
    }
)

print(html)

See Quick Example for an example.

The superfence supports the following options:

A comma separated list of line numbers or ranges of line numbers to show.

The line numbers are 1-based. If any line number is zero or negative, a warning is logged and the line or range are ignored.

If show_lines is omitted, it defaults to showing all lines.

Ranges are inclusive and are defined as follows:

• The ranges are specified as start:end, where start and end are the line numbers of the first and last lines to show, respectively.

• If start is omitted, it defaults to the first line. If end is omitted, it defaults to the last line.

• If start is greater than end, a warning is logged and the range is ignored.

• If start is greater than the number of lines in the code block, the range is ignored.

• If end is greater than the number of lines in the code block, it is set to the number of lines in the code block.

If you want to know how to build this project and contribute to it, please check out the Contributing Guide.