Twig Template Inheritance Issues - twig

Question

I'm trying to setup a clean structure for my Craft CMS install, but having issues with some very basic twig and a nice way to structure my things.
See this gist - why would my Navbar not show in this example?
Even better, I would like to structure my site like this - but it doesn't show anything? - another gist
Am I mixing the extend/block pattern the wrong way somehow? This feels so very basic and thus it's extremely frustrating. I would appreciate any help.

Answer 1

In your first gist, in index.twig, you extend base.twig correctly. However, you don't specify the contents of the navbar block, so the block defaults to the empty content that is set in base.twig.
You can change base.twig to include navbar.twig using the include function:
...
<div id="content">
{% include "navbar.twig" %}
{% block content %}{% endblock %}
</div>
...
You should also not extend base.twig in navbar.twig to prevent infinite recursion (base includes navbar, which extends base, which includes navbar, ...).
If you want the navbar to be overridable in index.twig and other files, you can retain the navbar block in base.twig and set its default contents to include navbar.twig:
...
<div id="content">
{% block content %}
{% include "navbar.twig" %}
{% endblock %}
{% block content %}{% endblock %}
</div>
...
Then, in index.twig, if you omit {% block navbar %}{% endblock %}, the navbar will use the contents from navbar.twig. Or you can also override the navbar block's contents:
{% extends "base" %}
{% block navbar %}
<h2>Overridden navbar</h2>
{% endblock %}
{% block content %}
<h2>Main content</h2>
{% endblock %}
In your second gist, in index.twig, you can change {% block head %}{% endblock %} to {% include "head.twig" %} and so on. In head.twig and other files, you should again not extend index.twig to prevent infinite recursions.
I recommend taking a look at Twig's documentation about the extends tag to see how blocks and templates actually work. In your two gists, blocks and templates are not used correctly.