More jinja functionality

[LecrisUT]

Describe the feature you'd like to request

Currently only substitution works for direct expansion of variables. It would be nice to have support for {% for %} directives and so on.

Describe the solution you'd like

No response

Describe alternatives you've considered

I've tried simply parsing the files as jinja templates, but it fails at directives like :::{include} because of curly brackets. How does myst get arround this?

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[chrisjsewell]

I've tried simply parsing the files as jinja templates

Heya, to note, myst-parser does not use jinja to actually parse the file, but only for expression evaluation.

Parsing is done with a plugin to the Markdown parser, e.g.

from markdown_it import MarkdownIt
from markdown_it.tree import SyntaxTreeNode
from mdit_py_plugins.substitution import substitution_plugin

md = MarkdownIt().use(substitution_plugin)
tree = SyntaxTreeNode(md.parse(
    "An {{ inline_expr }}\n\n"
    "{{ block_expr }}"
))
print(tree.pretty())

gives

<root>
  <paragraph>
    <inline>
      <text>
      <substitution_inline text='inline_expr'>
  <substitution_block text='block_expr'>

expressions are then evaluated in a post-processing step

[LecrisUT]

Ok, it seems that the error I encountered was not on that side, and indeed I am able to hack in the jinja rendered with:

def jinja_render(app: Sphinx, docname: str, source: list[str]) -> None:
    """
    Render pages as jinja templates

    :param app: Sphinx app
    :param docname: Name of the doc file
    :param source: Single element list with the source as first element
    """
    if app.builder.format != 'html':
        # Only parsing html for now
        return
    file = Path(app.env.doc2path(docname, base=False))
    if ".j2" not in file.suffixes:
        # If the file is not explicitly a jinja template do not parse it
        return
    src = source[0]
    rendered = app.builder.templates.render_string(src, app.config.html_context)
    source[0] = rendered


def setup(app: Sphinx):
    app.connect("source-read", jinja_render)

Only issue there is I can't extract the filename so that id doesn't try to render non-jinja file. If you have a clue, that would be wonderful

[chrisjsewell]

You might want to have a look at https://pypi.org/project/sphinx-jinja/

[LecrisUT]

I did check that one out, and it uses directives. I want this one to be for the whole file. I've used this one for inspiration. Do you know how to extract the filename in general from app object?

[chrisjsewell]

app.env.doc2path

[LecrisUT]

Thanks a bunch! I'll update the comment above with a short implementation. Not sure how to share it more generally though