This is a nifty one.
I wanted to create manual categories for my coding posts, so I ended up doing something like this in my coding/index.html (a simplified excerpt):
<div>
<h3>Ruby</h3>
<ul>
{% raw %}{% for post in site.posts %} {% if post.categories contains "ruby"
%} {{ post.title }} {% endif %} {% endfor %}
</ul>
<h3>Javascript</h3>
<ul>
{% for post in site.posts %} {% if post.categories contains "javascript" %}
{{ post.title }} {% endif %} {% endfor %}
</ul>
<h3>Erlang</h3>
<ul>
{% for post in site.posts %} {% if post.categories contains "erlang" %} {{
post.title }} {% endif %} {% endfor %}
</ul>
<!-- and so on -->
</div>… which was really ripe for DRYing up. The problem was that the partial would need to accept a parameter of some sort (for the category name). The official Liquid documentation leaves much to be desired, but there’s a tiny part in the Templates section of the Jekyll documentation that saved the day:
You can also pass parameters to an include. Omit the quotation marks to send a variable’s value. Liquid curly brackets should not be used here:
{% include footer.html param="value" variable-param=page.variable %}These parameters are available via Liquid in the include:
{{ include.param }}
So I abstracted the above into a partial, naturally so:
<!-- _includes/post-category.html -->
<h3>{{ include.name | capitalize }}</h3>
<ul>
{% for post in site.posts %} {% if post.categories contains include.name %} {{
post.title }} {% endif %} {% endfor %}
</ul>and the resulting index.html:
<div>
{% include post-category.html name="ruby" %} {% include post-category.html
name="javascript" %} {% include post-category.html name="erlang" %}{% endraw
%}
</div>Neato!