www.netz39.de/_includes/blog/post_info.liquid

{% assign author = site.data.authors[include.author] %}
{% assign date = include.date | default: "today" | date: "%-d. %B %Y" %}
{% assign rrule = include.rrule %}

<div class="post-info">
  {%- if author.url -%}<a href="{{ author.url | relative_url }}" target="_blank" rel="noopener">{%- endif -%}
    {% if author.avatar  %}
      <img alt="Author's avatar" src="{{ author.avatar | relative_url }}" loading="lazy">
    {% endif %}
    <p class="meta">
      {% if author.name %}{{ author.name }} - {% endif %}
      {% assign x = date | date: "%m" | minus: 1 %}
      {% if rrule %}
      
      {% assign freq = rrule | split: ";" %}
      {% assign frequency = freq[0] | split: "=" | last %}
      {% assign interval = freq[1] | split: "=" | last %}
      {% assign byday = freq[2] | split: "=" | last %}
      {% capture transformed_text %}
        {% if frequency == "MONTHLY" %}
          {% assign days = byday | split: "," %}
          {% capture days_text %}
            {% for day in days %}
              {% assign day_of_week = day | slice: 1, 2 %}
              {% assign week = day | slice: 0, 1 %}

              {% case day_of_week %}
                {% when "MO" %}
                  {% assign day_name = "Monday" %}
                {% when "TU" %}
                  {% assign day_name = "Tuesday" %}
                {% when "WE" %}
                  {% assign day_name = "Wednesday" %}
                {% when "TH" %}
                  {% assign day_name = "Thursday" %}
                {% when "FR" %}
                  {% assign day_name = "Friday" %}
                {% when "SA" %}
                  {% assign day_name = "Saturday" %}
                {% when "SU" %}
                  {% assign day_name = "Sunday" %}
              {% endcase %}

              {% assign week_suffix = week | append: "th" %}
              {% if week == "1" %}
                {% assign week_suffix = week | append: "st" %}
              {% elsif week == "2" %}
                {% assign week_suffix = week | append: "nd" %}
              {% elsif week == "3" %}
                {% assign week_suffix = week | append: "rd" %}
              {% endif %}

              {% if forloop.first %}
                {{ week_suffix }} {{ day_name }}
              {% else %}
                and {{ week_suffix }} {{ day_name }}
              {% endif %}
            {% endfor %}
          {% endcapture %}
          {% capture month_text %}
            {% if interval == "1" %}
              Every month
            {% elsif interval == "2" %}
              Every other month
            {% else %}
              Every {{interval}} months
            {% endif %}
          {% endcapture %}
          {{ month_text }} on the {{days_text}}
        {% elsif frequency == "WEEKLY" %}
          {% capture week_text %}
            {% if interval == "1" %}
              Every week
            {% elsif interval == "2" %}
              Every other week
            {% else %}
              Every {{interval}} weeks
            {% endif %}
          {% endcapture %}
          {% capture day %}
            {{ date | date: "%A" }}
          {% endcapture %}
          {{ week_text }} on {{ day }}
        {% endif %}
      {% endcapture %}
      {{transformed_text}}
      {% else %}
      {{ date | date: "%-d. " }}{{ site.data.language.str_months[x]}} {{ date | date: "%Y" }}
      {% endif %}
    </p>
  {%- if author.url -%}</a>{%- endif -%}
</div>