How to use breadcrumbs in jupyter notebook posts?

[KertLynx]

Suppose I have a page structure like this:

XXX
|__ YYY
|__ ZZZ

When the page YYY is rendered, it must show relevant breadcrumbs with links like XXX>YYY. Both XXX and YYY must have their hyperlinks. I use .ipynb files as source and use posts = (("posts/*.ipynb", "posts", "post.tmpl")) in conf.py to render them.

Is there an option to automatically show breadcrumbs on rendered pages? If not, is there an option to pass breadcrumbs information in jupyter notebook metadata?

Jupyter notebooks don't allow a list of tuples in metadata section. I can only pass a list of lists. I tried passing the following in metadata but it did not work.

"crumbs": [
            [
                "https://gitlab.com",
                "Cutting Edge"
            ]
        ]

What options do I have to achieve this?

[KertLynx]

I figured it out. Posting the solution here in case someone has a similar query.

I wanted my breadcrumbs to look like this:

Home > Category > Sub-category > post

with URLs only for Home and Sub-category.

I did it by modifying ui_helper.tmpl as follows:

## -*- coding: utf-8 -*-


<%def name="breadcrumbs(post)">
<%
    # Get the current language
    lang = getattr(post, 'lang', 'en')
    nav_links = navigation_links[lang]

    # Recursive flattening of NAVIGATION_LINKS
    def flatten_nav_links(items, parents=None):
        if parents is None:
            parents = []
        flat = []
        for entry in items:
            if isinstance(entry[0], tuple):  # submenu
                submenu, label = entry
                flat.extend(flatten_nav_links(submenu, parents + [label]))
            else:
                url, label = entry
                flat.append((parents, label, url))
        return flat

    flat_links = flatten_nav_links(nav_links)

    # Extract metadata
    category = post.meta('category') or ""
    title = post.title()

    # Always start with "Home" (linked to root)
    breadcrumb_items = [("Home", "/")]

    # Match with category
    for parents, label, url in flat_links:
        if label == category:
            # Add parent levels first
            for parent in parents:
                breadcrumb_items.append((parent, None))
            # Add the category itself, now with its URL
            breadcrumb_items.append((label, url))
            break

    # Finally, add the post title (no URL)
    breadcrumb_items.append((title, None))
%>

% if breadcrumb_items:
  % for i, (text, url) in enumerate(breadcrumb_items):
    % if url:
      <a href="${url}">${text}</a>
    % else:
      ${text}
    % endif
    % if i != len(breadcrumb_items) - 1:
      &rsaquo;
    % endif
  % endfor
% endif
</%def>