{#
    Reusable meta-tags macro for listing pages.

    Renders the standard set of Open Graph and SEO ``<meta>`` tags used on
    pages that list posts (tag pages, category pages, archive pages, etc.).
    Centralising the markup here means that a single edit to this file
    changes the meta tags for every listing page at once.

    Parameters:
        title (str): The page title used in ``og:title`` and
            ``twitter:title``.  The caller is responsible for constructing
            a meaningful title (e.g. ``"Tag: python - My Blog"``).

    Context variables used (passed via ``with context``):
        site_description (str): Site description used for ``description``,
            ``og:description``, and ``twitter:description``.
        site_keywords (list[str]): Keywords used for the ``keywords`` tag.
#}
{% macro listing_meta_tags(title) %}
<meta property="og:title" content="{{ title }}">
{% if site_description %}
<meta name="description" content="{{ site_description }}">
<meta property="og:description" content="{{ site_description }}">
<meta name="twitter:description" content="{{ site_description }}">
{% endif %}
{% if site_keywords %}
<meta name="keywords" content="{{ site_keywords|join(', ') }}">
{% endif %}
{% endmacro %}